I think they would understand that, after such a divisive primary, neither candidate would really be viable for a Presidential run (Obama not immediately and Clinton never at all). And they would fear irritating the supporters of the candidate not chosen.
Honestly, I think it would just irritate the supporters of *both* candidates if their candidate had to take a backseat to someone who wasn't even on the ballot in the primaries. I don't see either Clinton or Obama giving up unless they have to, and I can't see the Dem. leadership pulling the rug out from under both of them. It would look like they were overruling the voters (which they would be). Better to just try to discern some kind of "winner" out of the primary process, and then get behind that person.
Maybe. I think Obama would step aside as long as he were guaranteed the VP slot and the replacement was not a machine/insider candidate. But maybe I'm holding him in higher esteem than I should.
I agree with Morden. The remaining undecided superdelegates will line up behind whoever is leading after the primaries are finished. I don't think the pledged delegate count is going to be so close going into the convention that there will need to be some sort of compromise candidate. And even if it is I think the superdelegates would probably pick whichever candidate they feel has the best shot at the GE.