Welcome to the forum!

I like your flop and turn play.  On this river I probably check back, though.  First of all, it's hard for him to have a worse flush that calls your bet, while he can still play Q/J high flush this way, and sometimes nut flush as well (planning on x/r'ing on the turn and river).  Secondly, I don't think he can find a hero call with non-flush hands very often.  All draws on flop got there on turn/river, so if he's sitting with naked AA he can't really call.  Worse yet, if he has AA with Ah blocker he might decide to x/r bluff on the river, because your range is capped to Q high or even J high flush.  Actually, a competent opponent can x/r bluff with Qh blocker too if he thought you wouldn't check back turn with the nut flush.  I guess you can get called by straights and KK, but those make up only a small part of his oop 3b range.

That said, I prefer checking back river, and as played it's probably a fold unless you thought he was bluffing more than ~33% of the time.  Like I said, he could be doing this with Ah blocker I guess, but he probably would have bet the turn and shoved river with naked Ah blocker more often than not.

I would fold on the flop. With only a low flushdraw you have reverse implied odds.

Folding the flop doesn't make sense. This board doesn't exactly smacks OOP's range since it has 2 low cards. He should slow down on a lot of turns, and since we're IP we can choose if we want to realize our equity, or bluff. Our 66 blockers might come in handy as well on those cards.

It is more of a float than a pure value/equity call, but it's for sure profitable.

Just to point this out, you would rarely ever have the A high flush here. Trapping rarely occurs in PLO, unless you know player tendencies. Even the nut flush is vulnerable, so your check is a weak flush, a set that was looking for a safe turn or a wrap hand. At this point you have a bluff catcher, his range can for sure include the nut or second nut here.

u got owned.  that's what happened