I do not serve gluten to guests at my house, because they don't know how to not contaminate everything in their path. Only a few select people who understand me are allowed to consume gluten around me, haha. I always put it like this if I am given trouble with it by someone.
"If you were allergic to peanuts and had a peanut-free kitchen, would you still serve peanuts to your guests?" And when they respond "No, that would be ridiculous!" I say, "Exactly!!!!" and it drives the point across well.
I think the idea of a taco bar is a good idea. Then you can only put out gluten-free taco shells/nacho chips (if anyone asks if you have tortillas just say "oops only bought hard shells!"), plus all the toppings that are naturally gluten-free. Also, meatballs are really easy to make ahead of time if you cannot find them pre-made, and heat them up the day of. A crock pot is great for that. You can make baked pasta and people can never tell the pasta is gluten free. Buy some big foil pans, throw in cooked pasta/sauce and some cheese on top, hands-off preparation just pop them in and out of the oven. For grilled items, you could do meat and veggie skewers, those you can put together ahead of time and they cook up quickly.
If you do a cheese/fruit platter, you can probably get away with serving gluten-free crackers as well, people will just think they are some fancy brand. But for me, I try to not waste so much money on food people will possible turn their nose up at, so I usually will not buy a gluten-free substitute item to serve to guests except for pasta, I stick to things that are naturally gluten free.
If you do a taco bar, here is a recipe for mexican rice, you can multiply the recipe very easily, it is mild but tasty. Was given to me by a mexican friend
1 Tbsp. vegetable oil
1 C long grain white rice
2 C chicken broth
1/2 onion or 1 shallot
1 whole tomato,seeded
1 tsp. garlic powder
Salt & pepper to taste
Heat oil in saucepan over medium-low heat. Add rice and brown until golden brown. Carefully add chicken broth and grate in onion and tomato. Add garlic powder, salt, and pepper. Bring to a boil and then simmer 25 minutes, covered, until rice is done.
To prevent the rice from being soggy, use grated tomato towards total liquid volume measurement if the tomato is really juicy.