pokerJAH;336781 wroteguy in blinds likely has a flush draw or a 6 (trying to take down the pot with likely outs); MP could have small overpair (99/1010) or maybe 66, other two pair (since he was reluctant to call your push, don't put him on set). Is MP kind of player to not raise pre-flop with a big pair?
You actually think MP is limping with a small overpair? Most likely sb has flopped 2 pair and MP is open ended or has a flush draw. The blind is definitely scared of getting out drawn on a draw heavy flop and MP reluctantly calls screams "pot committed" and has some sort of draw.
I don't think you're good here with 57 personally. Especially with MP flatting SB shove (MP not showing strength but basically looking for 8 outs and SB already showing huge interest)