BYU has been a G5 level program in the relevant era and has never been considered a candidate for playoff consideration. Oregon can make independence work, but they won’t be considered for the playoff, like ND had been and will continue to be.
I disagree that Oregon wouldn't be considered for the playoff if they put together a 1-loss or undefeated season. Like BYU they could probably schedule 4 or 5 games against Pac12 teams and get a good schedule together nationally especially if they took on the Boise model of being willing to play anyone, anywhere. And Oregon is a much bigger draw than Boise plus they have scheduled well over the past decade or so and I'm sure they would be able to continue to do so.