Here is how I would rank them if Clemson loses and Iowa wins:
1. Iowa
2. Alabama
3. Oklahoma
4. North Carolina
All one loss teams (except Iowa), all conference champs.
If Iowa loses, I would put in Michigan St. as 4.
If Clemson wins, they are #1. #2 Iowa (if they win), #3 Alabama, #4 Oklahoma (or move OK + AL up and put in MI St. if they win).
This is what should happen if wins and conference championships matter more than the "eye test."