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And the mistaken opinion on St. Alphonsus was due to a lack of deeper understanding regarding the Ordinary Universal Magisterium ... which wouldn't be defined clearly until Vatican I.  Pursuant to the Vatican I definition, St. Alphonsus would no doubt have revised his opinion.  He simply saw a number of prominent theologians (big-named Jesuits) proposing this opinion and he called it less probable for that reason, because a minority of theologians held it.

But just because something remains uncondemned with explicit condemnation doesn't mean it's not heresy or error.  Again, Lutheranism, Pelagianism, Arianism, Nestorianism ... all these flourished for a significant length of time before they were explicitly condemned by the Church -- that did not make Arianism a "less probable" opinion, simply because it remained uncondemned; Arianism was a heresy from the inception.  It's just that it took people a little while to wake up to it and explicitly condemn it.

You've been citing theologians, mainly Msgr. Fenton recently, saying that "it is possible for non-members of the Church to be joined the Church and saved."
I was basically arguing with you in this fashion: even if the point were Church teaching, it wouldn't mean non-members of the Church have in fact been saved, since the Church without doubt does teach that God does not demand the impossible and that it is possible for a man not to sin, although there is no responsible adult for whom that is true - excepting again the unique cases of Our Lord and Our Lady, who received special graces in order to implement the divine will regarding man's redemption.
In short, the teaching, even if true, doesn't mean that non-members of the Church have been or are saved.
Btw, I challenge the teaching and you haven't established it by quoting Msgr. Fenton. But we don't even have to go there, as I said above.
You don't go around trumpeting as truth the presence of men who have not sinned in heaven simply because it is possible for men not to sin, do you?

Of course, the resistance to sin is impossible without grace. It is indeed possible for the bushman not to sin, or else he would not have personal fault.
However, salvation is a matter of efficacious graces which come from the hand of God, which include reception of the sacrament of baptism.  
As Ladislaus said recently, one may accept a version of BOD that entails a somewhat imperfect membership, but that is not non-membership.

This is one of the problems with Msgr. Fenton's terminology, and of course LOT's - nonmembers being saved or joined to the Church.