I was thinking Tweet first. He was sussed a fair bit at the start, but to me he looks like he's trying to at least solve the game with us.
But then last night he made this weird post about how you and Big Man have a better grip on which direction to go in, so he wants to take a backseat. Looks to me like someone who wants to blend in but not stand out.
Also, considering Smark/Haza/Brutus were all prime targets for town roles and Big Man/you/me were targets for scum roles, Ace looked like a reasonably safe kill option for the SK.