Big 12 probably does miss the playoff.
WVU is the only undefeated team left in the conference, and they probably lose to both Texas and OU.
OU would have to run the table from here on, and beat Texas in a rematch in the title game.
Even then, the SEC is getting two spots unless the wheels come off because they have the top 2 teams, plus six other ranked teams in conference, meaning any conference loss won't look bad in comparison.
Notre Dame will get a spot if they stay unbeaten. The selection criteria guarantees ND gets in if they run the table.
Clemson and Ohio State are both still unbeaten, and since the Big 10 was out last year, they will be in this season. It's just hard to see how the Big 12 gets in unless WVU runs the table from here on. Even then, I doubt they get in front of enough people since they are ranked sixth right now. Even a 1 loss Georgia or Alabama stays ahead of them right now.