Predicting whether Conan O'Brien will wind up on Fox is a tough call since we seem to lack a vital piece of info.
Years ago, after the debacle that was The Chevy Chase Show, Fox turned the 11 PM time slot back to its affiliates. The network doesn't program that hour and the local stations have filled it with their own shows — local news in many cases. Does Fox have the right to make them yank that programming (some of which is probably quite profitable for them since popular network programming feeds into it) and put on something like a Conan O'Brien show?
I dunno and you probably don't, either. I've been reading news reports and seeing all sorts of different answers — different enough that I don't trust any of them. Some claim that Fox would have to persuade all or most of its affiliates to yield the time for Conan. As much as I like Mr. O'Brien, he doesn't have a great track record lately, ratings-wise. On the old Late Night show, he was getting beaten by Craig Ferguson the last few months, even with Jay's Tonight Show delivering a strong lead-in. Conan's Tonight Show hasn't done that well unless he was about to be fired from it. That might make things difficult, clearance-wise.
On the other hand, some articles say Fox retains the right with its affiliates to just program an 11 PM show and force them to carry it. That would make things a lot easier.
So which is it? I guess we'll find out in the next few days. (It also might be some halfway-situation; i.e., the network can clear some markets and not others…)