Also, just forget Father Feeney. Stop trying to shoehorn him into some kind of plan that you're comfortable with, stop mulling over his statements and trying to make them click. Just trust God, trust the Church, and you can't go wrong.
Yes, Vatican II didn't happen overnight. But that doesn't mean the Church has allowed a heresy to be taught for five hundred years ( if you think implicit faith is a heresy ).
If you have a tendency to intellectual pride, as I do, you are ripe for incipient Feeneyism or some variant thereof. THe devil is ALL over it, trust me. Careful! The most important thing is to read good books, trustworthy sources. St. Alphonsus is accredited a great theologian by everyone; Father Feeney is not.
Implicit faith is a heresy. Was it condemned? I think so:
Condemned Proposition: "A faith indicated from the testimony of creation, or from a similar motive, suffices for justification" (Pope Innocent XI, Denz. 2123).
Note the "from a similar motive..."
Faith in the Incarnation of Jesus Christ must be explicit:
1) Our Lord Jesus Christ's words say so in the Gospels: "Whoever believes and is baptized will be saved, but whoever does not believe will be condemned." (Mark 16:16)
2) The Athanasian Creed states so, explicitly, and that was infallibly included in the text of the Council of Florence.
3) Implicit faith makes no sense. How does one believe something "implicitly"? It's like saying that I could be explicitly married to my wife yet, at the same time, be implicitly married to someone else, someone whom I do not even know. If such an absurdity were true, how would I ever "divorce" such an individual? How does someone with "implicit faith" ever get rid of it? Can they apostatize, even if they want to??
As for implicit faith being taught for 500 years, it wasn't. It was De Vega who first taught it, didn't he? So, the idea is around 400 years old, and it was never widely embraced when it first showed-up.
As for Pope Pius IX, in my (humble) opinion, he blew it, big time. He laid the foundation for Vatican II, but notice, none of his successors, until Pope Pius XII, followed in his footsteps. If anything, they tried to correct his ideas. In any case, we can read Pius IX's two statements in light of Tradition, but like Vatican II, one is not required to. And, that's the problem, isn't it?
As for Father Feeney, I think that he was a great priest and theologian. In essence, I think that he got things right, even though he got some of the details wrong.
As for St. Alphonsus, I think that he got some things wrong, which is the claim that you appear to be making about St. Augustine!