I had a little girl with a nut allergy and I carried the epipen everywhere with me. I was very careful to read every label but since I cook all my food from scratch we didn't run into any problems. With a child with so many allergies I agree that the safest thing for you to do is to have food sent by the parents.

I'm sure you will also do your best to try not to cook with the things that would cause her an allergic reaction in case for instance the smell of scrambled eggs caused her a reaction.