I don't think Notre Dame's defense will allow them to win every game on that schedule. 3-1 is more probabe and anything like 2-2 is a disaster to be sure, but 4-0 is a lot to ask.
That said, unless they play Iowa or Ohio State, I don't think they would be beating the 2 best teams in the conference anyway.
Notre Dame closes out the regular season with a visit to USC.
That will be interesting.
ND has a very tough schedule, one of the toughest. They could easily be 9-2 (again) and still rated in the top 7.