Anything without guacamole, sour cream, any creams, and Leche (that's pretty much watered down milk). But you could always say you can't have dairy, and they won't give you dairy products. But you could always order whatever you wanted, and say "No guacamole, cheese, or sour cream." they're pretty nice about making accommodations for their guests; My mother-in-law asked for Finely Chopped Vegetables and Meat AND no Pico, and they did just that for her.

You could ask and I'm sure they could figure something out

Menu doesn't change on a daily basis