Mozzarella has been fine for me, I don't react to it at all. So far I found also colby, jack, american are all ok for me. No swiss, though, very bad. :)
Favorite pizza substitution, for rare occasions:
beef pressed into pan, sauce on top, mozzarella on top, cook like pizza. Tastes the same, but no crust!
I guess you could do a mozzarella trial and see if you are ok with it. I'd be careful at first, not too much. :)