I am not totally sure there will be enough undefeated/1 loss teams to fill the top 4 this year. A 2 loss team getting in seems as possible as the rankings staying the same as they are now.
You will probably have one or more 1 loss (or fewer) teams from the SEC, ACC, Big12, and Pac12. My guess is that there will likely be 5-6 one loss teams. Even if there aren't enough to fill the top 4, the 2 loss teams will come from the SEC, Big12, or Pac12, not the ACC or B1G.
There are 3 Big12 teams with one loss right now. KState has TCU, WVU, and Baylor, so they could easily lose another one. TCU doesn't really have anyone else left besides KState, but Baylor also has Oklahoma. I could see KState beating Baylor and TCU, but losing to WVU, so that there isn't a 1 loss team. That said, it's much more likely that TCU or Baylor will beat KSt and finish with one loss.
There also will probably be a 1 loss team coming out of the B1G. Michigan State plays Ohio State, and Nebraska will likely play the winner of that game (both should have 1 loss at that point).
Good chance ND has one loss if it gets by A State.
I think the winner of Bama Auburn will probably have just one loss, not counting MSU.
In the Pac 12, Oregon may lose to Utah and A State may lost to ND or Arizona. Then the remaining one loss team could lose in the championship game. I think the Pac 12 has the greatest chance of having no 1 loss teams given the remaining scenarios.