They won't live long enough to fight Rebels, and Vader killed the Jedi himself.
I'm starting to wonder whether or not there will even be a RC2. They'll either find something for the Commandos to do during Ep. III, invent a story for after the Purge or maybe the entire squad goes rogue to find Sev.
"For where ever there is a n00b, there is MachineCult to make him cry and cringe."