For the remoulade sauce, combine the lemon juice, mayo, garlic, pepper relish, green onions, mustard, hot sauce, Worcestershire sauce, creole seasoning, salt, and pepper in a bowl and whisk well. Cover with plastic wrap and let it sit in the fridge for 1 hour.
Combine cornmeal, flour, garlic , garlic & onion powder, cayenne, salt and pepper together in a shallow dish.
Beat buttermilk and egg in a separate dish.
Dip the shrimp in the buttermilk mixture first, then let excess drip off. Dredge the shrimp in the flour and cornmeal mixture, shaking off any excess and transferring to a plate. Repeat until all of the shrimp have been coated. Let sit in the fridge for 15 minutes.
Heat 1-2 inches of oil in a large pan to 350 degrees F.
Fry the shrimp a few at a time until golden brown and crispy, usually around 3-4 minutes. Remove from the hot oil to a wire rack using a slotted spoon or spatula and repeat until all of the shrimp have been cooked.
Slice the rolls almost in half horizontally, leaving one side intact to act as a hinge and hold the sandwich together. Heat the butter and garlic in a small bowl in the microwave until melted. Open the bread spread with the garlic butter. Toast on a hot griddle, buttered side down.
Spread remoulade sauce over both sides of the rolls. Top with lettuce on one side, tomatoes on the other, then shrimp down the middle. Drizzle with additional sauce, then fold over.
Top with shredded lettuce and sliced tomatoes. Place shrimp down the center of each roll, then drizzle generously with the remoulade sauce. Close the sandwich and serve.