I'm in agreement with much of this. It's been a couple of days and then some since the game, and my recollection is quite similar to what you wrote in your first paragraph. I would add, that Buddy did have Hauser, initially, but cheated and came off him once Clark got by Kadary on the left side of the key.
At or around the same time, Q left Beekman and cheated towards the paint and then stayed there as you mentioned once Clark got deeper in the lane, while simultaneously MD moved off Huff and towards Clark. Again, this is based upon my recollection after watching numerous birds eye type replays on ESPN where they showed (and froze/stopped the footage) how our D completely collapsed around Clark.
The replays also show how Buddy is just standing there watching with his arms completed down at his sides vs. being up in a defensive position. I'm of the viewpoint, that if Buddy had given full defensive effort vs. just watching the play unfold there, it's possible/probable that he disrupts Clark's passing lane, at least to some degree, due to Clark's short stature. In doing so, who knows how things ultimately unfold. But hindsight is always 20-20. Once Clark's pass got to a wide open Beekman, he had all the time in the world get set/get the shot off. Q's run out towards him from his position at that point was futile.
You didn't answer my inquiry in regards to how often you've seen UVA/Beekman play this season. In any event, that's fine if you want to maintain your opinion/position of him currently not being a good shooter, but that doesn't mean it's true. I wonder what Bennett thinks about his shooting prowess? Perhaps he, as JB often spews, would say he doesn't miss in practice. As I mentioned, I saw a guy that appeared to have solid form and a very good looking stroke in shooting that buzzer beater.
I don't disagree (with all of UVA's options as you mentioned) that JB wouldn't take the bet of Beekman hitting the shot, however, I'm not convinced he was okay with those odds with him being as wide open as he was. I think, if I recall correctly, immediately afterwards the camera panning on JB, and JB still staring outwards towards the opposite end of the court where the crushing play just occurred. While staring outward, his arms were up in a way, signalling to his culprit player that just made the defensive blunder. To me, that was an indication along the lines of..."Houston, we have a problem."