I assume you are going vegetarian. Is your caterer familiar with vegetarian dishes?
Some vegetarian dishes which can be made in large quantities and are acceptable to all
Protein Salad (the regular stuff with beans, nuts , etc.)
Vegetarian Lasagna
Non-meat Italian "meatballs"
Vegetables without fat or meat
For the daring - flavor-baked tofu cubes and apricot dipping sauce

Rissotos made with veggies using water or vegetable broth are good. They can be made for a crowd, are filling and rich tasting.

Zuchini or eggplant cut in planks then grilled. Marinate with olive oil, herbs, and lemon juice. Serve as is, or wrap around other items to make a cold "roll". For example, wrap around a grain timbale (pressed into a mold then turned out - use rice, bulgur, barley, etc.) then skewered together with a rosemary stem. Or fold around a rice/other filling and tie with blanched chives into packets.

You could omit the marinating and serve them warm as well.

Veggie paella is also very colorful, and filling especially if you sprinkle almonds, peanuts or cashews on it before serving.

Baked polenta cut in diamonds and topped with grilled veggies. Very pretty yet easy to serve on a buffet.

Spinach pie made with phyllo pastry, spinach, dill, garlic, and lemon. You can add the eggs and cheese, but if you are ovo lacto, you can use silken tofu instead. This could be done on a cookie sheet platter and cut into squares or diamonds, or you can make individual pies using muffin tins and strips of phyllo.

Stuffed grape leaves or cabbage rolls using meatless rice or other grains (barley cooked in veggie broth is really good).

I could give more ideas if I knew more. Is it just vegetarian, or ovo lacto?

Wow...these recipe ideas are making me hungry-even as I'm enjoying "Fantastic" Foods Cajun Soup (vegan).

MMMm...
:)
Mark