Great poster.
I'm guessing Rock will win the belt and probably enter last (or second last) in the chamber match, making sure he doesn't take a whole lot of bumps. (Similar to SS 2011.) But if Cena wins the Rumble, there's no point in him being in the chamber match.
In regards to the WHC chamber match, they could have Ryback look dominant by winning the belt here in the chamber and then successfully defending it against Big Show at Wrestlemania one on one. Or have Big Show look dominant by winning the chamber match but that would mean Ryback taking yet another pin fall loss, so I doubt it. I somehow doubt Show/Ryback is happening at all come Wrestlemania.