Preheat oven to 350 degrees F. In a large saute pan on medium-high heat, heat olive oil; add onions and garlic; cook for 2 minutes. Add shrimp, tilapia and bay scallops; cook 3-4 minutes until about halfway done. Add Clamato(R), lemon juice, seafood seasoning, basil and rice; mix well. Cook to heat through.
Remove from heat; blend in Monterey Jack. Spoon mixture into peppers, place in a lightly greased baking dish, cover with foil and bake for 20 minutes. Remove foil and top with Cheddar; bake 5 more minutes or until the cheese is melted.