Some thoughts
Agree a lot will change by the final poll. It would be a crime if oregon had to play Ohio St 2 years in a row in the 2nd round. I hope it works out that somehow the seeding avoids intra-conference matchups in the first 2 rounds.
I have a hunch that Oregon, USC, Iowa, and Wash are going to knock each other out by playing each other, but if one of them can make an undefeated run to end the season, they will be the Big Ten's 3rd team.
Michigan is more simple. If they beat Ohio St, they will be the Big Ten's 4th team. If they don't beat Ohio St, they won't make it into the CFP.