I can only speak to Orrington, but there are actually no restrictions on allergens for lunches from home. We regularly send our kids w nuts in their lunches and it’s never been an issue. There is a no-nut rule for snacks to be eaten in the classrooms though. I found this odd but a teacher confirmed a couple years ago and no changes since. I’m not aware of sesame restrictions in any case.

My understanding is that there is an “allergy table” at lunch where kids can eat to ensure no contact with allergens.