It undefeated at the end of the regular season.

That would mean both teams would be in the Top 10 for sure. My guess is that Cincy would be around #5 (with their schedule, there's no way the committee would put them higher than that), and BYU around #6.

It wouldn't really matter what the other teams in the Top 10 did or didn't do, or how many losses they have. The committee has successfully rigged the system against any P5 team, and is especially partial to SEC teams.

My guess is that the 4 teams in the CFP would be Alabama, Georgia, Oregon, and Oklahoma, each with at least one loss, and I would guess that Oregon and Georgia would each have a couple of losses. In this scenario, Cincy and BYU could be the only unbeatens in the country, and would still be on the outside looking in. And the double whammy against these two interlopers would be pitting them against each other in a NY6 Bowl (most likely the Fiesta). That way it wouldn't matter what the outcome of that game is, they can still say that it's just two G5 teams playing against each other which proves nothing about their capabilities compared to the "top" P5 teams (despite each of them having 1 or 2 losses prior to the CFP selections).