[xerxes]

I'd limp re-raise on the flop. Not to narrow the field, but for value.

UTG had 2 cards. Maybe an 8 or a 9.
SB is harder to say. Maybe had a 7 and wanted to play against UTG, but wimped out when everyone was in on the flop. A7s? Or he had a middle-sized overpair?

I'm a noob, so I'm just practicing my reads and thinking out loud here. Don't take it as gospel!