2 bets to me on the turn with a set of jacks, and I'm confused.

[Glurfle]

MP3's limp-reraise after a limper and before a poster doesn't mean much to me. I think it's an easy cap preflop. I'd put MP3 on an okay Ace, a medium pair, or some stupid connector before I'd worry about AA/KK.

I'd 3-bet the turn. Lots of flush draws and pair+gutshot draws out there, plus all kinds of two pairs can be out. If you get capped, then you can just call the river.

Once it's checked to you on the river, I'd bet every time and expect to get called by at least one person with two pair well over 67% of the time.