I would just smooth call, and here's why:
If we flat call, we're giving any other villain 3:1 pot odds
to draw to the flush, which is a 4:1 draw. So he's still making a mistake if he calls the original pot sized bet. Plus, we have no reason to build the pot, since we're getting Becici's stack anyways on the turn (since he's so short). I'm gonna argue against conventional wisdom and say flat call this bet. We likely won't get anyone tagging along, but its worth a stab.
Then just put the whole table all in on a non-diamond turn . Also, we're not afraid of Becici chickening out on us if a scare card comes are we? He's already so committed I don't think he can get away from this hand if the Ad/Kd hits on the turn.