If Red Bull pulls it support, that team may not exist next year. Dietrich Mateschitz owns 50% of STR and next year Red Bull and STR won't be able to share Adrian Newey's design. He's said his share of STR is for sell. If no buyer is found, he'll probably pull his support from STR. I can't see Berger continuing on out of his own pocket.
I think Seabass is a very talented driver, but got his chance at F1 with a poor team. Plus he got his chance a little late in his driving career. I know he's not that old, but considering the youth movement in F1 over the last decade, the track record for guys starting at his age isn't great. He may have an interest in coming back to race in the US, but it wouldn't surprise me to see him sign with Puegot if his F1 career ends.