Look at how God acted in the lives of the saints. Of course those living in invincible ignorance CAN be saved. We see evidence of this throughout church history where people were miraculously bilocated to teach ignorant Indians the faith, as happened with Venerable Mary of Agreda.
Actually, there is a perfect work to describe this- By the Theologian Francisco de Vitoria on the discovery of the Native Americans and their relation to invincible ignorance. I didn’t invent this.
“And it is certain that
the Jews who were away from Judaea, whether they were in sin or not, had
invincible ignorance about baptism and about the faith of Christ. Just as
there could at that time be a case of invincible ignorance on this matter,
so there may also be nowadays among those who have not had baptism declared
to them.
But the mistake which the doctors in question make is in thinking
that when we postulate invincible ignorance on the subject of baptism or of
the Christian faith it follows at once that a person can be saved without
baptism or the Christian faith, which, however, does not follow. For the
aborigines to whom no preaching of the faith or Christian religion has come
will be damned for mortal sins or for idolatry, but not for the sin of
unbelief, as St. Thomas (Secunda Secundae, as above) says, namely, that if
they do what in them lies, accompanied by a good life according to the law
of nature, it is consistent with God’s providence and He will illuminate
them regarding the name of Christ, but it does not therefore follow that if
their life be bad, ignorance or unbelief in baptism and the Christian faith
may be imputed to them as a sin.”
https://en.m.wikisource.org/wiki/De_Indis_De_Jure_Belli/Part_2
The point he is making is that if they die without faith they will be damned for mortal sins, but not for the sin of unbelief, because their ignorance is invincible, therefore it excuses the sinfulness of their unbelief, but does NOT justify them since they have these other mortal sins for which they will be damned, given they DIE in this ignorance.
Go to the link and do a word search for invincible ignorance and read what comes up. The debate was whether all unbelief has the nature of sin. It does not. Yet the ignorant are not saved by the non-sinfulness of their unbelief.