Is that 'No' to all my questions? If not, how does one who believes in Articles 1 & 2 but only has "implicit faith" in Articles 3 & 4 ever commit apostasy?
By professing a belief in Paganism or Naturalism, possibly.
The problem is that someone in this condition is known only to God. That's why these people are not considered members of the Church, which has a visible membership. The other problem is that you cannot seem to grasp that the Church has not condemned implicit Faith and you are not required to believe it. Explicit Faith in all four items I mentioned is the common opinion.
I think that the Church did condemn "implicit faith for justification" for reasons that I have already stated. I realize that "the theologians" may not agree with this (the sole exception appearing to be Father Brian hαɾɾιson), but as most of them in today's Church openly support "gαy sex," I am not sure what your point is.
The "known only God" condition seems even more queer to me. We all agree (I hope) that infants who die without Baptism do not attain the Beatific Vision, both those born to Catholics and non-Catholics alike. If one is born in a non-Paganistic and/or non-Naturalist religion (they share some similarities), how does such a child ever acquire his/her "implicit faith"? Seems kind of unjust for the One and Triune God to exclude someone from Heaven who, at age 6.9, dies before the Age of Reason, but give "implicit faith" to some child who dies at age 7.1, even though both kids have never received sacrament Baptism.
So, if Jews, Muslims, etc., are in a state of grace via their "implicit faith," why not have some communion with them? And, why exclude Pagans and naturalists? With just a little more "theological development," why not say that one only needs "implicit faith" in all 4 articles of faith?!
"The theologians" are, by the way, not a reliable source for theology, because their opinions, unlike theology, keep morphing. It's a vacuous"appeal to authority," something that Sam hαɾɾιs likes to do when he appeals to the atheistic makeup (+90%) of the United States National Academy of Sciences.