The Pac-12 will have just 6 bowl eligible teams. So, if UW makes the 4-team playoff and Colorado/USC to Rose, the Las Vegas and Cactus Bowls won't have Pac-12 teams. Here is how I see the Pac-12 bowl picture right now:
Playoff: UW
Rose: Higher ranked of Colorado or USC in final CFB committee standings
Alamo: Lower ranked of Colorado/USC
Holiday: Washington State
Foster Farms: Stanford
Sun: Utah
Bowl Ineligible: Cal, Oregon, Oregon State, Arizona State, UCLA, Arizona.
I would not be surprised at all if Michigan and Clemson just trade places. Michigan won't get punished severely for losing to the #2 team in 2 OTs.
IF UW doesn't bump to #4:
The UW/CU winner gets the Rose. If CU upsets UW, then the Huskies probably stay ranked high enough to get an at-large bid for a January game, the Rose gets SC (who would be higher ranked at that point, and a bigger draw anyway). Then the Alamo gets to pick between Colorado and us. If the Alamo takes us, the Holiday gets Colorado. If the Alamo takes Colorado, the Holiday gets to pick between us and Stanford. Holiday probably gets us (and then FOster Farms gets to pick between Stanford and Utah), but if Holiday takes Stanford we have to go to Foster Farms. We can't fall to the Sun in this scenario.
If UW beats CU, or if Clemson gets upset, that might be enough to move UW into the top 4 (as long as the Wisconsin-Penn State winner doesn't jump over them). That would set up a very similar scenario to above.
Except: USC will move to #11 this week, with Louisville's loss. #8 Oklahoma and #10 Oklahoma State play next week. If Oklahoma wins, USC rises another spot to #10 in the final rankings, and then
they could get the Cotton. Colorado falls out of the top 10 (probably) and
could still end up in the Rose. Then we either get the Alamo or Holiday, and can't fall to Foster Farms.
Honestly, I'm having a hard time coming up with a scenario that puts us anywhere but the Holiday or Foster Farms. Rising up to the Alamo requires UW, CU, and USC to all go to NY6 games (which isn't likely). Falling to the Sun requires that only the conference champ gets a NY6 game - which also seems unlikely.