Oh man... I know how to do gluten free, but not soy free. Do you want to cook your food in the fire, or have a potluck or BBQ on the side? I'm assuming you want to cook all food in the fire. I googled vegan marshmallows to see if you could make s'mores, but they usually have soy protein in them. You should make hobo dinners. Have a bunch of diced potatoes, corn, different beans, crumbled soy- and gluten-free veggie burgers, bell peppers, onions, asparagus, and root vegetables sitting out buffet-style. Everyone gets a sheet of tinfoil and fills it with whatever they want, then folds it into a packet and cooks it in the fire for like 15 minutes, until the hard vegetables are tender. You should also have olive oil, herbs, salt, pepper, and any kind of yummy sauce your guests can eat to go with the veggies. You can also have fun things like sun-dried tomatoes and artichoke hearts. For dessert, you can make banana boats: slice a banana in half, put a couple tablespoons of chocolate chips or pieces in there (hope you can find soy-free chocolate), wrap in tinfoil, set in the fire for five minutes, eat with a utensil.