Lad, Stubborn and Pax, I would like to thank all 3 of you for your explanations of all this. You all have put my mind at ease in regards to this teaching. It has helped me avoid being a Donatist in dealing with most of the trad clergy.
It seems to me that if a R&R defender were to point to their "loose" BOD teaching because of a perceived interpretation of St. Thomas Aquinas and St. Alphonsus, would it stand to reason that that same line of thinking of authoritative doctors and theologians defending their perception of what Trent teaches would also apply to doctors and theologians in regards to heretical popes, especially post Vatican I and pre Vatican II? In other words, what's the real difference if you end up pitting doctors versus doctors for the respective issues? No trying to derail.
You are absolutely correct. The teachings of the Fathers on a BOD/BOB were pure speculations and as such could be right or could be wrong - - that's the price of speculating. There is no doctrine of the Church that might be wrong hence, BOD is not a doctrine. The same goes for St. Robert et al and their ideas regarding sedeism. Pure speculation is all it is and all it can ever be - until the Church makes the decision definitively. Until that happens, the default position remains the man elected is the pope.
In the case of a BOD as regards Justification, while the Church at Trent did not explicitly condemn the idea, neither did she teach the idea. As for salvation, She infallibly taught at Trent that the sacrament is necessary.
Which is to say that even if it is possible for one not baptized to die in the state of justification, because they did not receive the sacrament of baptism they cannot enter heaven. Lad has been saying this forever, that lacking the character of Baptism prevents entrance into heaven.