As to the Notre Dame discourse, I think the only way a deserving ND gets squeezed out of the playoff is if there is a concerted, coordinated effort to sabotage their status as an independent in an effort to force them to join a conference. I imagine anyone involved with that effort would face some kind of severe financial blowback whenever that coordinated sabotage eventually becomes public knowledge (it always does at some point).
With that in mind, I think there's zero chance they leave a deserving Notre Dame out of the playoff for a similar-in-record SEC or B1G team.