I think Cena coming in kicking his ass and then stripping of the belt will probably be the correct course of action.
Not bloody likely. They seem to be viewing a Cena/Carlito rematch as a golden ticket, so I wouldn't be surprised to see THIS happen: Cena's introduced as the 4th man on Team Guerrero, and Carlito bails and gets counted out following a slugfest. Heck, Cena can get counted out, too.
Then, when Carlito's healthy (ideally Armageddon, Royal Rumble if needed) they have the rematch.
I sure hope Carlito doesn't drop the title to Cena unless CCC is majorly injured. Even then, I'd rather have him drop it to someone else. Cena is a three time champion, and the US Title is just a prop for him. Hopefully CCC gets a decisive win over him, and Cena moves up to the main event. But then again, who is the last heel aside from HHH that they put over strong in a big mathc? I can't remember.
This reminds me of last year when Hardcore Holly got disqualified before the match even started at last years Survivor Series to set up a match with Lesnar. I don't know how this is gonna work but i don't think Cena can return at least before the Rumble. If they do decide to strip him of the belt i can't think off the top of my head who they would replace him as champion. I mean ifCena does come back at Survivor what kind of angle can they do again to take him off TV for even more time. It just doesn't work. My guess would be we don't see Cena for the rest of the year.
You do realize that bookers don't book spots in matches, don't you? The booker (in this case, Heyman for discussion) decides who goes over, why, and how it affects the story. The road agents and the wrestlers themselves decide the finish.