The thing about your entrees is, most people will take a meat and some ziti, and you don't have anything that could serve as an entree for non-meat eaters. My suggestion is you make the ziti meatless (or at least 1 pan, and identify it).

Pot Roast of beef, 35 pounds boneless beef
Cheddar Baked Boneless Chicken Breast w sauce, 1 pound raw chicken per each 4, use small pieces, so that 2 is a serving and 1 is what the people who take both will take.
Ziti- 9-10 pounds dry pasta, maybe some left