I would think he's going to WWE, simply because if he were going to All Elite, he wouldn't have said he's leaving NJPW. That is, unless the entire group is trying to swerve the public. Because from everything I've read, All Elite wants to keep working with NJPW because they feel it will help establish their brand. Maybe NJPW said that won't happen? We will see.......
Omega does this every year after Wrestle Kingdom. It means nothing. It's a great marketing tool for him to generate interest in himself while he takes a rest.
Gedo took the belt off of him because he was unsure about Omega's status. Omega's contract runs until Jan 31st, so there's no way for a possible Royal Rumble surprise.