Thank you for being so considerate of those of us with food allergies and intolerances! It's nice that others think about those of us who can't eat "normal" food like everyone else. Like the one poster stated, those of us with food issues should just find something or eat beforehand--that completely defeats the entire purpose of getting together for the meal, which is that everyone is supposed to be eating TOGETHER!
My daughter is in pre-confirmation at church and we have to get together the first Weds of the month for supper and fellowship after. It is very, very seldom that anyone thinks of those of us with food issues and makes us something we can eat. If my daughter and I didn't eat our own supper ahead of time (again, defeating the purpose of everyone eating together, communing, and breaking fast), at the last meeting all I would have had to subsist on for supper was one cup of lettece salad (and very weak/cheap salad at that) and two pieces of pineapple. We were feeding about 40-50 people, so it's not like I can load up with a plateful of lettuce and fruit just for me!!
And to top it off, our pastor is a vegetarian.
Next month, the mom of a boy with Celiac disease and I got together (my daughter and I have gluten intolerance) and we're going to make sure that three-fourths of the supper--if not the entire supper--can safely be eaten by everyone there. I'm making a wild rice/bacon/mushroom combo and some gluten-free choc chip cookies from scratch as my contribution. (Sorry, but the pastor will have to pick out the bacon if he doesn't want to eat it.)
So I understand where you're coming from totally!
Go to the Web site Livingwithout.com and check out their receipes. They have lots of gluten and dairy free ideas, and many times, you can also find lots of receipes that will also work as vegetarian. And they will give you substution ideas.
Making gluten-free spaghetti/noodles and gluten-free pasta would help cover everyone nicely, along with a nice lettuce salad. Then you could make ground hamburger or ground chicken separately, and whoever wants meat on their spaghetti can do so. You could buy the Chebe mix that is gluten-free (made out of cassava) and make small buns for everyone. I usually put sheep cheese in the mix, but you can make them plain/without, and I use rice or almond or coconut milk in place of cow dairy. And if you make a gluten-free desert, like some cookies, then everyone can eat it. My family LOVES Pamela's chocolate choc. chip cookie mix. I make them with goat butter, but you can probably also make them with palm oil spread.
Good luck!