When you have to cook for a lot for people you want something good but that will make the least amount of mess and take you the least amount of time. Burritos can be a good option for that. The idea is to prepare as much as you can in advance and just roll them out at the last-minute.
Instead of spreading each tortilla with each ingredient, I make a casserole out of them. Layer a pan with all the ingredients you plan on using such as beef or chicken, refried beans, cheese, olives, jalapeno,salsa, hot sauce and onions. If doing it a couple of days in advance, stop there and keep in the fridge. When you are ready to roll up the tortillas heat the casserole until it is warm. Then top with your avocados and sour cream.
Rip off a piece of tin foil and lay a tortilla on top. I used a pie server to slice off bits of the casserole and lay them on the tortilla.
Next just roll up the burrito and then wrap it in tin foil.
This is something you can make in an afternoon and put a couple dozen in the freezer for future teenage snack attacks. I would not put on the guacamole and sour cream if they are to be frozen, just serve it on the side. If you are going to reheat in the oven the tin foil works great. If you are going to use a microwave be sure to wrap in parchment paper. I store them in a Ziplock bag. To keep warm during lets say a Super Bowl party, hold them in a crock pot or a roaster oven on a low temperature.
I hope this helps you put together a simple and easy meal for a crowd or just to save some time in the kitchen.