It's a hard call. I'm sure Houston has to be the favorite going in. But they play OU first game and Louisville midseason. Both of those games are at HOME though. I would imagine playing at Navy will be a challenge if they survive the others.
Temple is an interesting pick because they don't play anybody good. Penn State is their only regular season notable opponent. They don't even play Houston.
Northern Illinois has the best chance of going undefeated but they play NOBODY. No kidding.
Boise hosts Wash State and plays at Oregon State. They also get BYU at home. I would rank them as the second most probable.
Marshall has a workable schedule. They host Louisville and travel to Pitt. I would imagine playing at Southern Miss might be difficult. They are my number 3.
BYU simply cannot win enough games with their schedule. It is BRUTAL.
Southern Miss plays at LSU. ouch
LaTech and WKU are possibilities I suppose. But both of them have their biggest question marks at the most important positions. Both Texas Tech and Arkansas are known to lay eggs. WKU has to play at Bama. (a loss won't knock them out but would have to win the rest of their games)