Prep Oven & Dish: Heat oven to 400°F (200°C). Use an 8x11-inch baking dish that holds the four rolls snugly.
Make Garlic Butter: Stir together melted butter, olive oil, minced garlic, lemon juice, paprika, red pepper flakes, and 1 tbsp parsley. Pour two-thirds into the baking dish and spread across the bottom. Save the rest for brushing.
Dry & Season: Pat fish fillets and shrimp dry with paper towels. Mix salt, pepper, garlic powder, and 1/2 tsp paprika, then sprinkle evenly over fish and shrimp.
Fill & Roll: Place 3 shrimp at the wide end of each fillet. Roll up snugly and place seam side down in the baking dish.
First Bake: Brush tops with remaining garlic butter. Bake uncovered for 12 minutes until fish turns opaque at edges.
Add Cheese: Sprinkle mozzarella and Parmesan evenly over rolls. Spoon a little butter from the dish over cheese.
Finish Baking: Return to oven for 8 to 10 minutes until cheese is melted and bubbly with golden spots (broil 1–2 mins if deeper browning is desired).
Rest & Serve: Check that fish reaches 145°F (63°C) and shrimp is pink. Rest 3 minutes. Top with fresh parsley and serve hot with lemon wedges.