I guess if we're still keeping Lesnar out of the Rumble something else has to happen. Which is annoying 'cos I like clean and easy setups like that. My next go to would be to have something happen during a multi-man tag match .
But yeah, Owens would end up being a face in an Owens vs Authority program. But that's fine. He can still do all his heel things to people as need. Technically it would be heel vs heel, but the crowd would be behind Owens, hence tweener designation.
You can just have him feud with a face while he's doing it to keep him heel.
Doing a Rumble clash isn't clean and easy because of the other focuses that are involved in that match.
Technically, if Owens is going against the Authority, the face is whoever the fans will cheer regardless of whether either side will cheat to win. Anti-heroes are still babyfaces in the world of professional wrestling if their antagonist is getting booed like the Authority will over Owens. A tweener is in the middle. Any established feud between one person and another or a group is devoid of tweeners unless someone in the group stays neutral on it.
Every single face run by Flair still involved heel tactics but he was still a face and not a tweener.