Think the OP hit the nail on the head.
In the B12 most of the teams have not played the meat of their schedules yet. And this next 3 or 4 games is everything to them.
However to be fair, there is only 2 undefeated teams left in the B12, and that is Oklahoma St. with Oklahoma and Baylor left. And Baylor with Oklahoma St, and TCU left. So as long as all of the B12 teams have 1 loss at the end of the season. I feel they are out.
In the PAC, as long as ND doesn't lose another game, and defeats Stanford, I feel that they are out of the running as well.
This leaves:
The SEC champ (either Bama or Florida) as long as they don't lose another game until they play 1 another
The B1G champ (either Ohio State or Iowa) as long as they emerge undefeated from the CCG
Clemson as long as they stay undefeated.
What ND needs for help:
Oklahoma St, and Baylor to lose a game
Anyone except for Clemson to win the ACC
Stanford to win until they play ND, and then lose to ND. (but win the conference)
And of course ND to win out. If all of that can happen. ND has a spot. Outside of that, with that 1 loss, ND does not control her destiny.