Is the College Football Playoff already set or can drama this weekend change things up?

-Right now, the top 4 is: Alabama, Notre Dame, Clemson, and Ohio State. Clemson has 1-loss, but they are a favorite over Notre Dame, mainly because Trevor Lawrence is back this time…who gets in if Clemson loses again, though?

-If Ohio State loses to Northwestern and Clemson loses to Notre Dame…who ends up in the playoff?