Here are the arguments for each of the one-loss teams to be #3, IMO...
Alabama: (1) best win of any team in the country (55-0 at home over aTm), (2) loss was one of the top five "best losses" (23-17 on the road against one-loss Ole Miss), (3) one of the best OOC wins of the year (33-23 on a neutral field over West Virginia) and (4) statistically, 25th in Scoring Offense, and 3rd in the country in Scoring Defense.
Auburn: (1) Probably the 2nd best win in the country (41-7 at home over LSU), (2) probably 2nd "best loss" (38-23 on the road against undefeated MSU), (3) also one of the best OOC wins of the year (20-14 on the road against Kansas State) and (4) statistically, 15th in Scoring Offense and 25th in Scoring Defense.
Oregon: (1) Probably the best OOC win in the country (46-27 at home over Michigan State), (2) one of the top ten "best losses" (31-24 at home against one-loss Arizona), and (3) 5th in Scoring Offense and 61st in Scoring Defense.
Notre Dame: Their only argument, IMO, is they have arguably the "best loss" of the year (31-27 on the road against FSU). If FSU loses, that would take away their only legitimate argument. They are 42nd in Scoring Offense and 14th in Scoring Defense.
Michigan State: They are like Notre Dame in that their best argument is in the quality of their loss - a road loss to Oregon. They are 5th in Scoring Offense and 20th in Scoring Defense.
Ole Miss: They have the best "second best" win - a road win over aTm, 35-20. Their loss is also a high-quality one - a road loss at night to LSU, and that was only by a score of 10-7. They are 50th in Scoring Offense and 1st in Scoring Defense. Being 1st in Scoring Defense is important, IMO.
Georgia: Their OOC win over Clemson is a good one. They are 9th in Scoring Offense and 19th in Scoring Defense.
I think Alabama, Auburn, and Ole Miss stand out. They all have high quality wins, high quality losses, and are statistically strong on either offense or defense or both.