Pius IX didn't teach salvation outside the church. With his statement about the mind, body, and soul he is saying God can search and see these people are sincere and enlighten them with the graces needed for salvation. You also didn't bring up Cantate Domino from The Council Of Florence or any other eccumenical councils besides Vatican II. You also attempted to put words into Aquinas's mouth by saying he thought they adequately knew the gospel. Furthermore, Pius XII clarifies that implicit desire simply means one who has desire, but is not a catechumen, so when read in that context Suarez and De Lugo are not teaching salvation for those who don't know the gospel. The idea people who don't know who Jesus is are somehow magically going to Heaven is completely nonsensical.
In his Commentary on the Sentences, where Aquinas responds to the question of whether explicit faith in Christ is necessary, he considers these two objections, among others:
"1. It appears that faith being explicit is not necessary for salvation. For grace and free decision is enough for salvation. But the gratuitous habit of infused faith is not enough for the explicitness of one’s faith, and neither is free decision informed by grace. Rather, the teaching of faith making it determinate must come for that, since faith comes from what is heard (Rom 10:17). Therefore the explicitness of faith is not necessary for salvation.
"2. Furthermore, no one is damned by what he cannot avoid. But if someone is born in the forest, or among unbelievers, he cannot possess in any distinct way knowledge about the articles of the faith; for no teacher of the faith is at hand, nor has he ever heard mention of the faith. Therefore such a one is not damned, and yet he does not have explicit faith. Therefore it appears that the explicitness of faith is not necessary for salvation."
And here's how he replies:
"1. In things that are necessary for salvation, God never abandons and has never abandoned a man seeking his salvation unless he remains so due to his own fault. Whence the explication of things that are necessary for salvation would either be divinely provided for a man, through a preacher of the faith, as is clear with Cornelius in Acts 10, or through a revelation. With such supposed, it is within the power of his free decision that he go forth into the act of faith.
"2. If such a one does what in itself belongs to the pursuit of salvation, God would provide for the salvations of such a one in one of the described ways."
So, depending on where you put the emphasis, Aquinas could be read as saying, contrary to objector #2, the unbelievers of his day (Jews and Muslims) were not truly in a state of invincible ignorance, but rather, because God does not withhold the things necessary for salvation, God has provided that preachers have made the Gospel known to them, leaving them to choose whether to make an act of faith or not. Or, more conservatively, Aquinas is saying that God ensures that preachers make the Gospel known to those who have what you could call a predisposition to faith, while those who have a predisposition to unbelief, they may never hear the Gospel preached. So rather than an implicit faith, Aquinas is in a way proposing an implicit unbelief. So in other words, on this reading, Aquinas is saying everyone in his day has either heard the Gospel preached, or has preemptively rejected it before having a chance to hear it.
Other theologians from around the same time, though, were more explicit. For example, the Franciscan Alexander of Hales, who like Aquinas taught at the University of Paris and was writing a generation or so before Aquinas, wrote in his Summa Theologica:
"With regard to what is necessary for salvation, a distinction must be made, because either ignorance cannot be avoided, as in one who lacks the use of reason from birth, and this excuses these matters; or it may be avoided, as in the case of Jews and Pagans, and this does not excuse it."
That suggests that Alexander believed that all of the non-Christians of his day had heard the Gospel and therefore had no excuse for their unbelief.
But point being, the idea that there was an entire continent of millions of people who had never heard the Gospel was not something the 13th-century theologians had to consider, and their way of resolving the problem of unbelief among non-Christians seems preposterous in light of the situation that Christians discovered in the fifteenth and sixteenth centuries.
Second, with regard to de Lugo and Suarez, the claim that they're not talking about those who haven't heard the Gospel is a bit absurd. All of the Spanish theologians I mentioned were members of the missionary orders that were attempting to evangelize the Indians in the Americas, and so the theological questions raised by these efforts would have been the very things they were debating in their theological schools back in Spain. One of the books were Francisco de Vitoria discusses the theme of implicit faith is literally called "On the Indians" (De Indis). Suarez is quite explicit that he is talking about those who have never heard the faith or those who have heard it, but sufficiently to elicit an act of faith, and he specifically identifies the Turks and the "Indios" in the Americas as among those he is talking about. These discussions were clearly about the question of what to think about those who had never heard the Gospel, because the medieval solutions were inadequate to what the Spanish missionaries encountered.
As for Pius IX, I would agree he is saying that "God can search and see these people are sincere and enlighten them with the graces needed for salvation," but you're begging the question. Textually, he's clearly talking about people who are in a state of invincible ignorance in regards to the tenets of faith, so the straightforward reading is that "the graces needed for salvation" are referring to a path outside the normal means of explicit faith. That's supported by the fact, as I mentioned in the article, that Pius was advised theologically by Giovanni Perrone, S.J., who in his own writings had defended the idea that explicit faith was not required for the salvation of those who hadn't heard the Gospel and that God could work through other means. As I also pointed out, Perrone arguably helped author Quanto Conficiamur Moerore, based on textual similarities between the document and his own writings, and who in his own writings defended the idea of implicit faith as sufficient for salvation.
Finally, you're misreading the quote from Pius XII. As you can clearly see in the second sentence of the paragraph I cited, he's talking about people in a state of invincible ignorance regarding the Gospel, which obviously would not apply to a catechumen. He's referring to non-Christians, which should be apparent by the fact that this is written in response to Leonard Feeney. What he's saying in the first sentence is that we can understand the implicit faith of those who don't know the Gospel in a way that's somewhat analogous to how we think about "baptism by desire" for catechumens. Similarly, that's why in Mystici Corporis Christi Pius refers to an "unconscious desire and longing" to be part of the Church, which of course would not be the case of a catechumen, who is conscious of their desire to fully belong to the Church.
Also, Pius XII gives the answer to your question on the Council of Florence in the same document:
"Now, amongst those things which the Church has always preached and will never cease to teach, there is also this infallible declaration which says that there is no salvation outside the Church.
"This dogma, however, has to be understood in the sense attributed to it by the Church herself. The Saviour, in fact, entrusted explanation of those things contained in the deposit of faith, not to private judgement, but to the teaching of the ecclesiastical authority."
As he goes on to explain there and in Mystici Corporis Christi, those who lack explicit faith because of lack of knowledge of the Gospel, but who have the "unconscious desire and longing" I already mentioned are not "outside the Church."
Pius IX didn't teach salvation outside the church. With his statement about the mind, body, and soul he is saying God can search and see these people are sincere and enlighten them with the graces needed for salvation. You also didn't bring up Cantate Domino from The Council Of Florence or any other eccumenical councils besides Vatican II. You also attempted to put words into Aquinas's mouth by saying he thought they adequately knew the gospel. Furthermore, Pius XII clarifies that implicit desire simply means one who has desire, but is not a catechumen, so when read in that context Suarez and De Lugo are not teaching salvation for those who don't know the gospel. The idea people who don't know who Jesus is are somehow magically going to Heaven is completely nonsensical.
In his Commentary on the Sentences, where Aquinas responds to the question of whether explicit faith in Christ is necessary, he considers these two objections, among others:
"1. It appears that faith being explicit is not necessary for salvation. For grace and free decision is enough for salvation. But the gratuitous habit of infused faith is not enough for the explicitness of one’s faith, and neither is free decision informed by grace. Rather, the teaching of faith making it determinate must come for that, since faith comes from what is heard (Rom 10:17). Therefore the explicitness of faith is not necessary for salvation.
"2. Furthermore, no one is damned by what he cannot avoid. But if someone is born in the forest, or among unbelievers, he cannot possess in any distinct way knowledge about the articles of the faith; for no teacher of the faith is at hand, nor has he ever heard mention of the faith. Therefore such a one is not damned, and yet he does not have explicit faith. Therefore it appears that the explicitness of faith is not necessary for salvation."
And here's how he replies:
"1. In things that are necessary for salvation, God never abandons and has never abandoned a man seeking his salvation unless he remains so due to his own fault. Whence the explication of things that are necessary for salvation would either be divinely provided for a man, through a preacher of the faith, as is clear with Cornelius in Acts 10, or through a revelation. With such supposed, it is within the power of his free decision that he go forth into the act of faith.
"2. If such a one does what in itself belongs to the pursuit of salvation, God would provide for the salvations of such a one in one of the described ways."
So, depending on where you put the emphasis, Aquinas could be read as saying, contrary to objector #2, the unbelievers of his day (Jews and Muslims) were not truly in a state of invincible ignorance, but rather, because God does not withhold the things necessary for salvation, God has provided that preachers have made the Gospel known to them, leaving them to choose whether to make an act of faith or not. Or, more conservatively, Aquinas is saying that God ensures that preachers make the Gospel known to those who have what you could call a predisposition to faith, while those who have a predisposition to unbelief, they may never hear the Gospel preached. So rather than an implicit faith, Aquinas is in a way proposing an implicit unbelief. So in other words, on this reading, Aquinas is saying everyone in his day has either heard the Gospel preached, or has preemptively rejected it before having a chance to hear it.
Other theologians from around the same time, though, were more explicit. For example, the Franciscan Alexander of Hales, who like Aquinas taught at the University of Paris and was writing a generation or so before Aquinas, wrote in his Summa Theologica:
"With regard to what is necessary for salvation, a distinction must be made, because either ignorance cannot be avoided, as in one who lacks the use of reason from birth, and this excuses these matters; or it may be avoided, as in the case of Jews and Pagans, and this does not excuse it."
That suggests that Alexander believed that all of the non-Christians of his day had heard the Gospel and therefore had no excuse for their unbelief.
But point being, the idea that there was an entire continent of millions of people who had never heard the Gospel was not something the 13th-century theologians had to consider, and their way of resolving the problem of unbelief among non-Christians seems preposterous in light of the situation that Christians discovered in the fifteenth and sixteenth centuries.
Second, with regard to de Lugo and Suarez, the claim that they're not talking about those who haven't heard the Gospel is a bit absurd. All of the Spanish theologians I mentioned were members of the missionary orders that were attempting to evangelize the Indians in the Americas, and so the theological questions raised by these efforts would have been the very things they were debating in their theological schools back in Spain. One of the books were Francisco de Vitoria discusses the theme of implicit faith is literally called "On the Indians" (De Indis). Suarez is quite explicit that he is talking about those who have never heard the faith or those who have heard it, but sufficiently to elicit an act of faith, and he specifically identifies the Turks and the "Indios" in the Americas as among those he is talking about. These discussions were clearly about the question of what to think about those who had never heard the Gospel, because the medieval solutions were inadequate to what the Spanish missionaries encountered.
As for Pius IX, I would agree he is saying that "God can search and see these people are sincere and enlighten them with the graces needed for salvation," but you're begging the question. Textually, he's clearly talking about people who are in a state of invincible ignorance in regards to the tenets of faith, so the straightforward reading is that "the graces needed for salvation" are referring to a path outside the normal means of explicit faith. That's supported by the fact, as I mentioned in the article, that Pius was advised theologically by Giovanni Perrone, S.J., who in his own writings had defended the idea that explicit faith was not required for the salvation of those who hadn't heard the Gospel and that God could work through other means. As I also pointed out, Perrone arguably helped author Quanto Conficiamur Moerore, based on textual similarities between the document and his own writings, and who in his own writings defended the idea of implicit faith as sufficient for salvation.
Finally, you're misreading the quote from Pius XII. As you can clearly see in the second sentence of the paragraph I cited, he's talking about people in a state of invincible ignorance regarding the Gospel, which obviously would not apply to a catechumen. He's referring to non-Christians, which should be apparent by the fact that this is written in response to Leonard Feeney. What he's saying in the first sentence is that we can understand the implicit faith of those who don't know the Gospel in a way that's somewhat analogous to how we think about "baptism by desire" for catechumens. Similarly, that's why in Mystici Corporis Christi Pius refers to an "unconscious desire and longing" to be part of the Church, which of course would not be the case of a catechumen, who is conscious of their desire to fully belong to the Church.
Also, Pius XII gives the answer to your question on the Council of Florence in the same document:
"Now, amongst those things which the Church has always preached and will never cease to teach, there is also this infallible declaration which says that there is no salvation outside the Church.
"This dogma, however, has to be understood in the sense attributed to it by the Church herself. The Saviour, in fact, entrusted explanation of those things contained in the deposit of faith, not to private judgement, but to the teaching of the ecclesiastical authority."
As he goes on to explain there and in Mystici Corporis Christi, those who lack explicit faith because of lack of knowledge of the Gospel, but who have the "unconscious desire and longing" I already mentioned are not "outside the Church."
Learned quite a bit about the history of grace and salvation, particularly by lesser-known writers who wrote at the same time as "the usual suspects."
I'm always happy to see Catholic.theologians writing about this important subject!
I am glad you saw the article, I was going to send it to you otherwise, since I know this is an area you are interested in!