I'd do tacos and both corn and flour soft tortillas so guests could make/fill their own taco or tortilla wrap.
I'd have fried mince, shredded chicken, fajitas, black beans, pinto beans and refried beans as fillings.
Then the condiments: salsa, guacamole, shredded cheese, soured cream, chives, fried onions, jalepenos.
And a big bowl of Mexican style rice - just regular rice, but you do it like this:
put some oil in the bottom of the pan, fry up some onion and green and red pepper and garlic and salt and pepper. Then add in the amount of rice you need. When it starts to go brown, IMMEDIATELY add the amount of water you need, but replace about 1/4 of the required water with tomato passata. Then cover and cook as normal.