OK, it is clearer.
Understanding the bride's ideas, I have to say that if it is self serve at dinner time and the amounts are wrong, she will run out of food before everyone eats, which is about as bad as it gets...
Also, serving a reception, you have three basic times to deal with: the hour or so right after the service, while the couple gets their pictures done and the food, etc is set up, where you need a nibble table, usually 3 items with punch in a simple wedding; the "meal/main" service; and the party snack and cake service if dancing etc occurs after.
So here is how I would suggest to re-work the plan for 50:
Nibble table: 1/2 deluxe fruit tray for 100, prepared on several trays (serve trays one at a time); 6 pounds cheeses and spreads; 3-4 pounds crackers; 1 gallon hot dip (artichoke? spinach? seafood? queso?) crock pot
Shrimp (cook as needed in large electric skillet) and Grits (plan on keeping warm in slow cooker and serving in chafing dish),
Have someone serve the shrimp, and have it is last position on the food table. Allow about 3 ounces ready to eat shrimp and 1/2 cup grits per 100.
A brilliant addition here would be a mixed salad of marinated whole button mushrooms and cherry tomatoes- alternate topping and a fine addition to the general menu
Sliced Pork Tenderloin (cook ahead) on crostini, possibly sub boneless chicken thighs or consider pulled pork;
add carb filler, such as an Italian pasta salad, tiny roasted new potatoes...
Add veggie item such as the Parmesan spinach squares on this site
Vegetables; roasted or grilled instead of just crudites