WSOP $1,500 closer: cooler or did I misplay this hand?

Cooler (mostly).

Preflop should be a min raise but SB is likely to call anyway. Still its possible you could have survived if SB folded.

Flop is fine.

Turn is what it is. Personally I would just call and just call the river but it looks like SB has 7x. I call because it could be 76/75 but it is surprising that SB wouldn't lead out with a set or two pair on this board so I get the jam.

Raise preflop, you can have some limps a little shorter but you generally shouldn't.

Mostly a cooler but I'm curious what your reasoning is for jamming the turn.

He played it like he had trip 7s: check call flop with top pair, bet heavy on turn with trips. The river could have had a lot of scare cards for me and given my stack size, decided to jam.

It's a cooler but you should still assess the line you took and how it could be improved

Why are you limping the button? Please don’t play tournaments if you are going to make such bad mistakes. Open to a min raise please.
Never open limp

There's a time and place for all plays - I wouldn't be so close minded. Maybe the blinds are 3b/jamming at a high rate - we still have a range advantage limping. Maybe we limp knowing the blinds will raise a very wide range and we can call/jam over - just blindly min raising isn't necessarily the best play.

Limping the button is a good play sometimes. I don't see why OP is doing it here with a strong hand for the button, which can even call a 3!, but not a big hand to trap with. Unless there is some dynamics like a you expect to get 3! a lot, I don't see the point in it.

Flop sizing is bad. I know small sizing is in style, but this is a wet board 3-way, so I would make it a lot more than 1/4 pot.

Strong agree. We can make it as much as half pot here, maybe even more. Against recs multiway you will usually get at least one call, so I don't see the point in betting small with a good hand.