I don't think it's a huge leak but when we raise, we're representing the straight, so we're relying on UTG to make mistakes and call with most of his 2 pairs and set hands without proper odds. If UTG correctly folds those hands, then we're just isolating ourselves against the part of his range which we don't have great equity. Given that he's playing with a half stack, this could suggest he may call improperly, but he also has tight-ish stats which could suggest he may be able to get away from his hand.
As far as his range, my experience when I see this kind of flop donk is some hand that is OOP, has some equity, doesn't want to have to ch/call a big bet but knows the flop doesn't hit our range hard, though we can certainly represent wider than AA given that we're iso-raising on the button. A lot of times I see exactly hands like 567, 467, etc., moreso than small pairs, especially given that he is somewhat type and so more unlikely to be playing these hands early and OOP. Also, if he did have 55 or 33, I would expect him to check-raise often to extract value knowing we're almost always C-betting this board.
For the range listed, I would try to make it more specific, like having the hands in his range fall within the top 20% of hands but excluding some percent of hands that he would raise UTG. As shown, hands like J733, 55Q2, etc., as including in the range which are very unlikely. I would also remove some combos of KK b/c he's probably still raising many of the stronger ones preflop like KKQTds, etc.