collards greens, 1/2 cup cooked per person
a bottle of sport pepper vinegar would be called for here.
green beans, 10 pounds
sliced tomato, cucumber & onion salad, start with 1 pound tomatoes per 4, add the rest to make the ratios right

potato salad, 7-8 quarts
dirty rice, start with 3 pounds dry rice. Consider using the oven to cook, directions on site
cornbread dressing, 2 gallons

gravy, I like plenty, about 1/2 cup per person, and remember the smothered beef has some in the count.

Biscuits would be the right bread. See the angel biscuit recipe on site for foolproof (well, nearly foolproof) help. 2 pounds real butter.

Hope there will be a lovely fruit cobbler for dessert!