lasagna, 4 9x13 pans, make one meatless unless you are certain you have no vegetarians among your guests
chicken Alfredo, consider doing 3 9x13 and doing 18 pounds grilled small chicken breasts/cutlets separately, allows the no carb people to have something to eat
salad, use 1/2 the amount for salad on the plan for 100 list, or do the classic relish tray from the veggie tray page, or the antipasto veggies.
French bread- at least 6 pounds- 8 if there are some serious bread eaters-