How may pieces of each do you recommend?

Also, you have what is probably too many fried/grilled/baked foods for easy prep in a home kitchen; this menu would require a couple of cooks in the kitchen for the whole time due to the onion rings, fries, grilled cheese and sliders. You could alter by doing meatball sandwiches, oven fries or potato wedges, oven baked onion rings, nacho cheese sauce with chips instead of grilled cheese and large rectangular pizzas cut into squares or fingers. Fried anything for a group this size is a real headache.