[Dagger78]

An unknown SB has a few hands here, some possiblities are AQ or AJ(less likely since you hold one of each), KT for the flopped straight, a set, or a flush draw.

AQ is a decent possibility
Flopped straight is also well within an average 2/4 players hand to call pre-flop in the sb, but most qould slowplay to the turn.

A set is unlikely since he probably would have 3-bet with QQ or AA and you hold an Ace and Jack.

A flush draw is also possible and people love to CR flush draws in mutli-way pots.

Considering all of this I'm STILL not sure what we should do here. I think flat calling the flop and raising a blank on the turn is correct here, if we get 3 bet on the turn by the SB that sucks but we'll have to call down.