About your flop play: With 2 people already committed on the flop, you are missing too much value by not 3 betting here. Against just one person there are merits to just calling the flop and checkraising the turn.

Given that you just called the flop, I would check this turn with the intention of raising every time. The MP's flop raise forced the two other players to call 2 small bets cold, this implies that MP is more likely to have a top pair hand like Ax than a draw, which means he is very likely to bet this turn with his made hand, and he still may bet the turn if hes on a draw anyways. So your turn play is fine, not all good plays work all the time.