Preheat oven to 450°.
Place bread in a food processor, and pulse 10 times or until coarse crumbs form to measure 3/4 cup.
Heat a medium nonstick skillet coated with cooking spray over medium heat. Add onions, parsley, and garlic; cook 5 minutes, stirring constantly. Remove from heat; stir in fresh breadcrumbs, Italian breadcrumbs, and the next 4 ingredients (Italian breadcrumbs through black pepper). Place oysters on a jelly roll pan. Sprinkle breadcrumb mixture evenly over oysters.
Bake the oysters at 450° for 7 minutes or until the edges of the oysters curl. Serve with lemon wedges.