Hmmmmmmmm I haven't really thought about it... I think Ace would stick with Jack, being the case that he is technically her guardian, and help him with the store and become a mercenary for the MRF and the Conclave. Her interaction with the rest of the group would probably be minimal but she'd keep in touch as much as she can as well as visit the other members of the group on her days off.

Edit: gosh dangit Templar! You should have said that sooner, yah tall galoot! I oughta bonk you on the noggin! ..... If only you were a giant....