It's Cody or Rock. That's it. Realistically there's no other options.
Oh Jesus the fact that anybody believes that Sami Zayn or Cody Rhodes have any legitimate chance of winning shows how delusional some people are. Zayn gets his shot at Reigns at Elimination Chamber, then teams up with Kevin Owens to dethrone the Usos. Cody Rhodes fights Seth Rollins for the vacant WWE Championship after Reigns gets stripped of it, Rock wins the Rumble and fights Reigns at Mania for the Universal Championship.
That's how it's going to go, doesn't matter if you like it, that's the current plan.