Now you need to reconcile what *you want* to believe of the Archbishop to what he actually said regarding the pope-heretic question:
For anyone who's honest, the object truth of the matter is that Archbishop Lefebvre, with the exception of a period in the early 1980s where he was seeking a practical arrangement with Rome to make the "experiment of Tradition", was always open to the possibility of sedevacantism.
He also stated clearly that the Holy Ghost's protection over the papacy (as taught also by Vatican I) would preclude this degree of destruction. He hesitated to unequivocally affirm sedevacantism because he could not in his mind definitively (and with the certainty of faith) rule out some other possible explanation for how this happened. But he upheld the principle that the R&R here are now denying while claiming to be the "faithful heirs" of Archbishop Lefebvre.
Plenus in particular here pretends to speak for the Archbishop, creating his own sock puppet version of the Archbishop that he pretends is regurgitating the same stuff that he is posting here. But the real Archbishop was open to sedevacantism, did NOT consider it a "danger to souls" (except, as I said, in the early 1980s), and affirmed the principle that the Holy Spirit protects the papacy from this kind of destruction.
Plenus also pretends to speak for the Resistance ("the Resistance hold that sedevacantism is a danger to souls"). Well, Bishop Williamson has said that it's possible Jorge's not the pope and also has said that it's quite understandable why someone would hold that he isn't. Avrille also said that it's understandable. Father Chazal stated that +Vigano is a Resistance bishop (at least in spirit) ... after the latter declared it to be morally certain that Jorge is not the Pope. I should think I'd listen to Bishop Williamson, Avrille, and Father Chazal regarding what "the Resistance" hold rather than to Plenus.
So Plenus is misappropriating Archbishop Lefebvre AND making claims about what the Resistance hold that don't stand up to reality ... based on his wishful thinking that they support his position. They do not.