I know getting in off the waitlist is really rare but would have a letter specifically for notre dame from my principal look good? She knows me well and really likes me so it would be a good letter
I can’t say for sure about Notre Dame, but I think following up with a letter from the principal and one from yourself is a good idea. The conventional wisdom is that is you really want to get off the waitlist, let a school know you will be attending if offered a spot. But only do that if you are really serious about taking the spot.
FWIW check the admissions website. There is a blog post up about what to do (and not do) if you are on the waitlist.
It won’t hurt. If ND is your top choice you should also send a letter if continuing interest to your admission officer – if it is true you can say “if admitted I will attend”. Then whatever happens you will know you gave it your all. Good luck.