Shredded Roast Beef Sandwiches 50# (caterer providing)- OK with the chicken, meatballs and wings
20 dozen buns- For the 60 pounds meat, 300 buns- or consider getting some slider buns for the kids and light eaters. It takes 5 buns or 12 slider buns per pound.
Wings -1 roaster full (caterer providing)- definitely none left
Shredded Chicken 10# leftovers from another event
I am making the following:
Meatballs 20# (appetizer size), will take 6 quarts of sauce

Cheesy potatoes - 1 roaster (maybe 2???)- at least 2- they only make about 70 people's worth per roasters
Baked Beans -4-5 gallons (roaster full), I usually allow 3 gallons per 100

Pasta Salad 8# of pasta 2 gallon glass jar full
Marinated Bean Salad 6# 2 gallon container
I usually do 2 gallons per 100 of beans, 3 gallons of pasta salad (about 5 pounds dry pasta)

4 lettuce Salads I am ordering or making 24# of:
Multi Layer Salad 9# skip, see note
Greek Salad 6# do 10-12 pounds lettuce and additions as appropriate
Cole Slaw do 4 gallons
Broccoli Cauliflower do 4 gallons
You do not need the multilayer salad.

18 cases of beer; beer drinkers usually drink 4 each over a longish party, so this is more than enough for about 100 beer drinkers
200 bottles water- consider 2 per person, either keep left cases or return
8 cases of soda (we do not drink this so do not want any left over)
6-8 gallons of iced tea, 2-3 unsweetened, would be a good addition.

lemonade or 36 juice boxes for the children, you could do as much as 8 gallons for the non-beer, non-soda drinkers
Pies and cookies ordering from bakery. not sure on amounts yet on those.
I suggest you look at the dessert planning page. A sheet cake serves 60. Cookies and bars, get small ones, eg cut giant brownies into 4, and do 1 of each flavor per person, up to 4.

Fruit tray 2 large, not a lot. You can make these cheaply, it takes about 4 hours to prep enough for 200, see the fruit tray page; or at least supplement with 8 quarts of strawberries.