I think your evaluation is spot on, except I think even an undefeated Utah team (current) is still fighting Georgia for the 6th spot.  There is a reason Utah's chances of making the CFP are around 8%.  Far too much has to happen with those ranked above them.  Namely LSU vs Alabama.  LSU needs to destroy Bama, which is most likely not going to happen.  Clemson should win out because nobody in the ACC will beat them.  Even if Ohio State suffers a loss, it will look better than Utah or Oregon's, so the BIG 10 is in with for sure.

This is why an 8 team playoff should exist.  Take the conference champions from the Power 5 schools, add three more variables, well probably two because of the love fest for Notre Dame every year.