I estimate 1 quart sauce per pound of raw pasta, and that usually divides 2/3 red and 1/3 white, or 1/2 red, 1/4 white and 1/4 green or other specialty. 4 ounces raw boneless meat per person for 1 meat, 5 ounces if there are 2 meat choices, people take more.

Here are some minimums. 2 gallons gives 200 people about 2 1/2 tablespoons per person
Steamed Broccoli, chopped, 3 1/2 gallons (about 40 pounds)
Artichoke hearts, 3 gallons, chopped, dressed in olive oil
Green onions, chopped, 6-7 pounds
Fresh Parmesan Cheese, shaved, 3 gallons
Sundried Tomatoes, 2 gallons
olives, sliced, 2 gallons
cooked mushrooms, 4 #10 cans, drained and buttered/seasoned

This table usually used for salad bars might be helpful for other items:
www.ellenskitchen.com/bigpots/plan/saladbar100.html

A self-catered buffet is a real challenge to the organizers, and things don't always come together as smoothly as hoped. By planning and setting up an appetizer area or "nibble table" which is ready when the guests begin to arrive, the cooks and servers have time to complete the arrangement of the dinner buffet. This is especially critical if there are children among the guests, or there is a wait before dinner, as at a wedding reception.

This does not have to be complicated. Three items, plus a punch, or two if one is alcoholic, are sufficient. Typically, include a fruit tray, a cheese tray and an attractive dip or spread; or you can go with a dinner theme such as TexMex with chips, salsas, Texas caviar and guacamole; Italian with bruschetta or antipasto; maybe shrimps or other cold seafood, if budget permits.