In addition, at a wedding there is a delay of an hour plus between the end of the service and the arrival of the wedding party for the reception. You MUST have some kind of appetizer arrangement, and for 250 people that requires at least 2 appetizer set up areas, and 3 is better. Plus a punch or beverage service. This does not have to be extensive. A fruit tray, a cheese tray and one interesting dip or spread. And it is ESSENTIAL, or you will have distress and chaos as people wait.

pulled pork, 1 pound raw boneless pork makes at most six sandwiches, which serves about 4. So you are estimating enough, but here is an issue.
Up to 10% of your guests will not eat pork or will not eat meat at all. To provide options you can; make 1/3 chicken; make all chicken. In either case, provide at least a large crock pot full of vegetarian sausages (I recommend "Field Roast" brand)

potato salad, 10 gallons, or about 100 pounds of raw potatoes. Pasta salad (8 pounds dry per 100) is actually an easier prep.

baked beans-10 #10 cans or 20 pounds dry. Make some meatless/vegetarian and label, for the non-pork eaters

Add slaw, 7-8 gallons for sure. Strongly recommend you also consider also adding 5-6 gallons of marinated veggies or cucumber salad or cucumber and tomatoes.

dinner rolls- 12 pounds per 100. 3 pounds butter per 100.

3-4 quarts table sauce per 100.
1 gallon pickles per 100
8 pounds sliced onions per 100

Here is a real life note from a bride:
"The advice I would give to an amateur caterer is... at any event called "informal," your friends will volunteer to help you out, so you'll think there'll be people on hand to help you bring out the food, or clean up, or refill bowls.... But half of them won't. They'll offer to carry out the salt and pepper, then they'll lose the shakers, and they'll get drunk and disappear. That's just the way it often happens, and it's better to be prepared than disappointed! I was an event planner at the time, so I was prepared NOT to be helped by any of my so-called volunteers, and was very gratified by the four or five who did do what they said they would (and I thanked them effusively in person, in a toast I offered to them, in thank-you letters a week after the wedding, with gifts, and with a thank-you brunch at which they didn't have to do a thing). Anyway, because of the lack of reliable helpers, the food moved a little more slowly than I would have liked, which led to some harassment from angry guests who would corner me and my helpers and demand that we hop to it. (And I was the bride. So don't expect to be cut any slack!) So, make sure you have reliable helpers--it's very hard to be a first-time amateur doing it even with help, and I can't imagine it without."