I think this kind of thing has gone way too far and parents need to push back. Why are the schools taking these extreme measures? This isn't preschool but elementary school where children with alergies can be taught not to eat others' food. Restricting peanuts, fine. But all the rest is ridiculous. A child with dairy alergies will not become violently ill if the child next to them is eating dairy. They are actually listing BRANDS that you should buy! All of which are absolute junk non-food that are fueling an obesity epedemic in this country. If it were me I would ask for a meeting with the principal and say that I find the list offensive and that I have every right to bring homemade and home prepared food for MY child to eat. If they feel it's necessary, they should create a special table for kids who want to stick to the approved list.
I also don't understand why kids are constantly given snacks these days, especially if they're not going to have any nutritional value. Feed your child breakfast, preferably a high protein breakfast. My Kindergartener has no interest in snack because he has a big breakfast and lunch is at 11:30. Children can go a few hours without eating! We did it when we were kids. And incidentally we weren't as fat back then..