If we are going by storyline and build up Chris Jericho winning it would make perfect sense.
1. He's never won it so it would be something new
2. They have been teasing the Jericho/KO break-up for a while now so Jericho winning would finally make the best friends have to fight (the video packages would be epic)
3. Giving Jericho the Rumble win and Mania title shot would be a great "thank you" from the WWE for legit being the best thing on Raw this year (outside some New Day fukkery)
4. I don't think Finn will be back in time to compete in the Rumble, Rollins will be busy dealing with HHH, after last year's debacle WWE may hold back on giving Roman another Mania main event this soon maybe in 2018 but not this upcoming one, should be Kofi or Cesaro but they won't be allowed to win, Kevin Owens is currently the champion so he can't be in the Rumble... all there is left is Chris Jericho.
5. Both Nakamura and Samoa Joe should debut in the Royal Rumble match and one should win but I think both are still tied up in their feud with each other plus I can see both of them being used to sell tickets for the NXT TakeOver: WrestleMania Weekend special and both probably won't make their main roster debut until they do a Re-Draft special where Shane and Stephanie get to trade wrestlers to different brands and allowed to draft more wrestlers from NXT.