Combine first four ingredients in a bowl. Spread on a baking sheet coated with cooking spray.
Arrange fillets on top of vegetables; season with salt and pepper to taste.
Combine crumbs and next four ingredients; toss with melted butter. Divide crumb mixture evenly over each fillet, pressing into the fish. Bake 20 minutes, or until fillets flake easily when tested with a fork.
Sprinkle with scallion and serve with lemon wedges.