All my nephews (4 all up, 2 from my bro n 2 from my sis) have salicylate intolerances and 2 of them have the allergy to milk protein.
I am a bit scared for my DD Charlotte cause it runs in the family! (I had it as a kid too but back then they didnt really know much bout it, and I was allergic to artificial colours, preservatives and flavors so I wasn't allowed anything pretty much!!)
It is very hard to have kids with high allergies to foods that should be normal! It sounds like you are going very well though as hard as it must be!
Good luck and hopefully ds2 grows out of it soon!!