I've heard nothing, and the NW people I've talked to either don't know or aren't talking....
If I were a betting man, I would say that NW will move to B (since there is more room in B, globally speaking).
BUT, CO and UA will also likely move together once their partnership gets underway. If US is liquidated by then
CO could slide into at least some of their old gates, with a little retro-fitting like the current CO-NW connector hallway on C.
It all depends on the traffic, of course.
IF CO moves to A, DL COULD move to C, to make one big blended family.
Thoughts?