Rolls - 180 rolls- At least 18 pounds- 225 to 350, depending on size- 4-5 pounds butter
Roasted red potatoes - 60 lbs- OK, none left. Potatoes are cheap, consider adding a few more pounds
Fresh green beans - 25 lbs- at least 34 pounds
Cole Slaw - 25 lbs- you need 4 gallons- I would start with 30 pounds cabbage plus all the add-in and fixings.

You also need an appetizer table (two, actually) and here is why:

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 (6-8 gallons per 100), 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.

One appetizer service area One serving area is needed for each 100 guests.