If the top 4 win out, I think we have the Final 4 with the only question whether a UM win over OSU and in the Big10 Championship are enough to vault over ND. If any of 2-4 lose any game, it gets interesting and if Bama loses, shit gets REAL interesting.
That being said, I really wish ND's SOS gets exposed for how it weak it is. N.B. Rankings in parentheses that follow are current S&P. I may have the homer glasses on, but if UM wins out, there is no doubt in my mind that they should jump ND. UM's best wins are against PSU (12) and Wisconsin (13), with a matchup against @OSU (9) and another one against one of NWU (68), Wisco (13), Purdue (25), or Iowa (29) in a championship remaining, not to mention their win @MSU (30).
ND OTOH, has a week 1 win at home against UM obviously, but otherwise their best win is against Stanford (35) at home and @VA Tech (61). The rest of their schedule ranks in the 60s and 70s and a couple of the worst teams in the country to round it out. Even OU and WVU have had better SOS, to say nothing of UGA. ND may be one of the best 4 teams in the country, but they have not proved it to the same extent of these other conference teams. Until the committee dings them in a situation like this, ND will never consider joining a conference. Although I do accept the fact that their schedule usually produces much better competition - i.e. FSU at 75 and USC at 43 are unusually low. But this is why a conference schedule is important - unless ND joins the PAC12 there will always be good consistent competition on their schedule.