There are other things that would factor in to it.
- Who was your 1 loss to?
- Who did you beat in the conference championship?
- How did ND look in the rest of the season?
- What is your SOS at the end of the season?
You are speculating. And I strongly believe you are incorrect. Probably not this year but, ND could have a year (like next year) when they have 1 loss to the #1 team in the country (in the first game of the year), soundly beat multiple ranked teams and end the regular season ranked #2 or #3. I don't believe for a minute that with a resume like that, they would be automatically passed over by a 1 loss conference champ from the ACC, PAC or Big12.