Losing the BYU would not hurt Cincinnati's NY6 chances. They would still be ahead of anyone in the AAC, MWC, the Mac, he Sunbelt....so still the top G5 team. Meaning they get the auto bit.
Also, 10 and old BYU is not going to get bumped by a one-loss team from the PAC or B1G. There's no second team from the Big 12 to take their spot. And the ACC isn't putting 3 teams in or the SEC 4.