Even if they lose, Oregon isn't dropping from the top 10 (assuming the game is close).
But if Illinois can get a loss or too - they're out of the top 25 and aren't an option for additional Big10 teams in the playoffs. If they beat Oregon, they could jump quite a bit.
For similar reasons - I'd probably pick Texas to win. We want the top SEC teams to knock down everyone else so that no other SEC teams make it into the top 15. That means either LSU, Georgia, and Texas keep winning - or one of those three loses multiple games still.