Houston might actually be able to snag the 4th playoff spot, because it looks like 2 of the Power 5 conferences might have weak champions. The SEC, Big 10, and ACC Champions (assuming it's Clemson) will all get a spot unless something extremely major happens, and an undefeated Houston team would likely get in over a 1 or 2 loss Pac-12 and Big 12 team.
They'll be sending Oklahoma as their rep. They played a couple decent teams early, but they're still the best that league has to offer. While Baylor, WVU, and TCU have better records, those 3 teams are still garbage.
Yep if I had to guess it would be
SEC Champ prob Alabama
ACC Champ prob Clemson
Big10 Champ prob Ohio State
and Houston