#2 Shaq is a surprise Rumble entrant
We know that The Big Show is in the Rumble match. He's a staple of the match because it's a feat to eliminate him, so it's important for him to be there.
This year, though, the plan is still reportedly to do Show vs. Shaq at WrestleMania. That could mean that Big Show is in the match specifically to initiate a build-up towards the WrestleMania match.
Shaq could enter after Show clears the ring and they could have a stand-off. Eventually, someone else comes in and they eliminate him together, but then Shaq dumps Show out while he has his back turned.
WWE loves the celebrity involvement, and if Shaq vs. Big Show is the plan for WrestleMania, then I would not be shocked to see the former NBA All-Star as a Rumble match entrant.