Bama won't make it. Not one impressive win. Mercer? They had to come back to beat Mississippi State a four loss team. Strength of schedule. Yes Auburn beat them, but now Auburn is a 3 loss team.
If you put Bama in you'll leave out two conferences, The BiG Ten and the Pac12. That certainly isn't going to happen. Clemson, Oklahoma and Georgia for sure. I have no idea who is going to make the fourth spot. As I said before IMHO Ohio States loss to Iowa should kill their chances. This is a conundrum.