There might be some last-minute attempts by top 10 teams to orchestrate a play-in game. I would expect conferences to allow it if it gives their team a chance to move into the top four. I also think CFP is getting pressure to move back their final determinations a week, that would allow for these play-in moves.
The Big 12 reentering the discussion is bogus given the current one loss teams. Texas A&M at 9-1 with just a loss to Bama and a win over FL should be ahead of any Big 12 team. A two-loss FL team, assuming it loses in the SECC game, with losses to just Bama and A&M, should be ahead of any Big 12 team. ND, assuming they lose no more than their ACCC game, should be above any Big 12 team. If Clemson loses again to ND, there will be table pounding that they should be let in. Absent a loss to Arkansas, Bama is in.
There is the arrogance of some conferences of "this is my conference champion, they deserve to be in the playoff", and the 2020 reality of "perhaps one OOC game following our conference championship game will put us over the top". I'd love to see Bama sit a week, along perhaps ND and/or Clemson, and watch a weekend of FL, A&M, Cincy, Ohio State, Big 12 winner, and the Fightin' Mullets all playing and making a case for number 4.