I think there's a very low probability the committee keeps Oregon over Texas if Oregon picks up a second L and Texas remains a 1-loss team.
In the sense that perhaps Texas would get in over 1-loss Washington, maybe it doesn't matter who wins the PAC CG. Which I could actually see
I think mainly Texas needs FSU to lose. Michigan, UGA, the PAC 12 champion (loser is probably out), and then it's going to be Texas no matter what.
The biggest wrench in the works there is if Bama beats UGA. The committee will go through all kinds of mental contortions to figure out how to put both Bama and UGA in.
Guess we'll see.
Oh there's zero chance the committee keeps Oregon over Texas if the Ducks lose. But that will mean that Washington is undefeated and will be in over 1-loss Texas, regardless. Under the current rankings from the selection committee, the PAC is basically already locked in, which effectively locks Texas out, from that spot.
Assuming Texas wins which is hardly a foregone conclusion, and assuming the committee keeps Oregon over Texas this week, then a very simple way to look at it is this:
PAC champ is in no matter what.
SEC champ is in no matter what.
Michigan is in with a win
FSU is in with a win
So the only way Texas gets in, is with either a Michigan or FSU loss.
Of course, there's also the possibility you raise, that an Alabama win will make the committee want to put both Alabama and Georgia in. That gets really messy of course, since Texas would have beaten the team that beat Georgia. Guess we'll find out in a week.