I would find either explanation to be plausible, that he has no clue what the beatific vision is or that he literally meant that Kirk is already in Heaven -- and neither one speaks well of him, the former entailing crass ignorance of even the basics of the Catholic faith that he claims to be devoted to, that latter a Bergoglian-Wojtylan heretical view of salvation rooted in complete religious indifferentism.
I hate to say it, but I think you, for whatever reason, are blowing this unfortunate use of language way out of proportion. You are dead wrong in claiming that his use of the term in the context in which he used it could mean that he would entail himself in "crass ignorance of even the basics of the Catholic faith." Where is your evidence for that? Have you ever sat down with him and quizzed him on the basics of the Catholic faith??
If you were to ever challenge him face to face I think you would be surprised that he knows a lot more than perhaps you could ever imagine about what you refer to as "the basics of the Catholic faith." I have heard him defend the Catholic faith at length and I was surprised at his degree of knowledge, especially considering his presumed wretched upbring in the NO.
The theological term Beatific Vision does not even come up in the Baltimore Catechism, until No. 3, the one for high school students. Does that mean none of the young folks all the way up to high school who never heard the term, let alone knew its proper usage were entailed in "crass ignorance of even the basics of the Catholic faith?!"
I would venture to say that there may very well be all kinds of people holier than you, assuming for the sake of argument that you yourself are holy, who for whatever reasons were not taught with precision the use of the term "beatific vision" or in today's world even heard of it, but that didn't stop them from being holy Catholics.
Very shortly after Fuentes uses that term he's talking about Kirk coming "face to face" with God. If that's all that he said I don't think people would be jumping up and down trying to claim that implied that he was in heaven since so many Catholics, for better of for worse, simply equate that with the particular judgement. He is on record as saying there is no salvation outside the Catholic Church so he obviously knows that dogma. So the business of assuming that he meant Kirk who he knew was not a Catholic was in heaven is just bunk.
P.S. Fuentes is a self-described Catholic integralist who identifies with the traditionalist Catholic movement. Those who continue to endlessly harp on this forum and other venues about him being NO don't accomplish much more than their own echo chamber harping. It seems like you never hear them offering any evidence of what specific parish or chapel he goes to or whether he goes at all. All we seem to hear is the blanket gratuitous assertion/mantra that he is NO.