You got a Papal declaration on that, or is that YOPIOS?
No, I am pretty sure it is orthodox Catholic view. The differences that exist are in how much emphasis is put on the extrardinary character of such salvation by invincible ignorance.
A special case is the application of vincible and invincible ignorance to salvation. Failure to embrace the Christian faith (infidelity), total repudiation of the Christian faith (apostasy), and the post-baptismal obstinate denial or willful doubt of particular teachings of the Catholic faith (heresy) are objectively grave sins against the virtue of faith. Like any other grave sins, if they are committed with adequate knowledge and deliberate consent, they become mortal sins and will deprive one of salvation.Also like any other grave sins, their imputability can be removed, diminished, unaffected, or increased by the varying types of ignorance. Invincible ignorance removes culpability for the sins against faith, merely vincible ignorance diminishes culpability (sometimes to the point of being venial), crass or supine ignorance will affect culpability for them little or not at all, and hard hearted, affected ignorance will increase culpability for them.
For those who have had their culpability for sins against faith removed or diminished to the point of veniality, they are not moral sins and thus will not of themselves deprive one of heaven. A person who is ignorant of the gospel of Christ and his Church through no fault of his own (or, by extension, through his merely venial fault) can be saved-if he otherwise does what is required for salvation, according to the level of opportunity, enlightenment, and grace God gives him (CCC 847, 1260).
In such cases, people are not saved apart from the true Church. Though they are not "fully incorporated" into the mystical Body of Christ, they are "joined" or "related" to the Church (to use Vatican II's language) by the elements of saving grace God has given them. One might thus speak of them as having been "partially incorporated," though not obtaining membership in the proper sense (Pius XII, Mysitici Corporis 22).
Unfortunately, there are a number of erroneous views regarding salvation and invincible ignorance that need to be pointed out. First, the fact that someone is invincibly ignorant of the true faith is not a ticket to heaven. A person who is not culpable for sins against faith may still be culpable for other mortal sins-the same ones people of faith can commit-and may be damned on that account.
Second, the fact that someone is invincibly ignorant does not mean that they should not be evangelized. The farther from the center of God's truth a person is the more spiritual jeopardy they are in. Even if they are not culpable for sins against faith, the fact they are ignorant of the true religion and do not have access to the sacraments means that they are more likely to commit mortal sin and thus more likely to be damned. Christ did not leave us the option of only evangelizing some peoples (Mark 16:15) or of only teaching them some doctrines (Matt. 28:20). Consequently, it is a false understanding of evangelism or a false spirit of ecumenism that would suggest that classes of people can be left in total or partial ignorance of the true faith on the pretext that they are invincibly ignorant and should not be disturbed.
This is what the Catechism says about the moral conscience of all men:
IV. ERRONEOUS JUDGMENT1790 A human being must always obey the certain judgment of his conscience. If he were deliberately to act against it, he would condemn himself. Yet it can happen that moral conscience remains in ignorance and makes erroneous judgments about acts to be performed or already committed.
1791 This ignorance can often be imputed to personal responsibility. This is the case when a man "takes little trouble to find out what is true and good, or when conscience is by degrees almost blinded through the habit of committing sin."59 In such cases, the person is culpable for the evil he commits.
1792 Ignorance of Christ and his Gospel, bad example given by others, enslavement to one's passions, assertion of a mistaken notion of autonomy of conscience, rejection of the Church's authority and her teaching, lack of conversion and of charity: these can be at the source of errors of judgment in moral conduct.
1793 If - on the contrary - the ignorance is invincible, or the moral subject is not responsible for his erroneous judgment, the evil committed by the person cannot be imputed to him. It remains no less an evil, a privation, a disorder. One must therefore work to correct the errors of moral conscience.
1794 A good and pure conscience is enlightened by true faith, for charity proceeds at the same time "from a pure heart and a good conscience and sincere faith."60
- The more a correct conscience prevails, the more do persons and groups turn aside from blind choice and try to be guided by objective standards of moral conduct.61
This is the catechism on the salvation of the unbaptized:
"Outside the Church there is no salvation"846 How are we to understand this affirmation, often repeated by the Church Fathers?335 Re-formulated positively, it means that all salvation comes from Christ the Head through the Church which is his Body:
- Basing itself on Scripture and Tradition, the Council teaches that the Church, a pilgrim now on earth, is necessary for salvation: the one Christ is the mediator and the way of salvation; he is present to us in his body which is the Church. He himself explicitly asserted the necessity of faith and Baptism, and thereby affirmed at the same time the necessity of the Church which men enter through Baptism as through a door. Hence they could not be saved who, knowing that the Catholic Church was founded as necessary by God through Christ, would refuse either to enter it or to remain in it.336
847 This affirmation is not aimed at those who, through no fault of their own, do not know Christ and his Church:
- Those who, through no fault of their own, do not know the Gospel of Christ or his Church, but who nevertheless seek God with a sincere heart, and, moved by grace, try in their actions to do his will as they know it through the dictates of their conscience - those too may achieve eternal salvation.337
848 "Although in ways known to himself God can lead those who, through no fault of their own, are ignorant of the Gospel, to that faith without which it is impossible to please him, the Church still has the obligation and also the sacred right to evangelize all men."338
Finally, on necessity of baptism
1260 "Since Christ died for all, and since all men are in fact called to one and the same destiny, which is divine, we must hold that the Holy Spirit offers to all the possibility of being made partakers, in a way known to God, of the Paschal mystery."62 Every man who is ignorant of the Gospel of Christ and of his Church, but seeks the truth and does the will of God in accordance with his understanding of it, can be saved. It may be supposed that such persons would have desired Baptism explicitly if they had known its necessity.The scripture references are at source in the Catechism, inline in the Akins' article.
I believe, I presented the normative Catholic teaching fairly accurately in 152, but the above, particularly if you follow the links and check the scripture references should allow for a study in depth. Note in particular that an atheist (whose case you bring up in 162) is not invincible in his ignorance, since the natural law includes at least a raw concept of one Creator God, and a non-christian religious man loses his invincibility if his denial of Christ becomes active rather than culturally-determined and passive. Also note that in either case an accrual of good works does not seem to ever overcome obstacles to salvation due to apostasy or heresy committed with full cooperation of the informed will.