Tara poses a good question. How big a group will attend? Making snacks for 100 is a lot easier than make them for a 1000!!
Example, One of my kids recently observed a 10th reunion from their small Indiana High School With only 45 in the graduating class and half of them not attending, the event had about 40 people total. They had it at a local restaurant.
I graduated in a class of 640 (48 years ago) in SoCal. At the 40th reunion in 2000 they had 700 in attendance. It was decided that the location for our 50th whould have to have A LOT MORE handicapped parking spaces and less spicy and "chewy" foods in the menu ![;)][;)].
Know the size of the grroup may get you some more helpful suggestions.
Some of my thoughts.
1. Shrimp. cold peeled, with a spicy dip sauce.
2. Santa Fe Wraps cut about an inch thick for easy snacking
3. Long Veggies…Carrot Sticks, Scallions, Celery & Dip
4. Summer Sausage chunks on Toothpicks
5. Fruit Salad..Melon and Fruit chunks (w/toothpicks)