Season the shrimp with ½ teaspoon of the salt. Spread some flour on a rimmed sheet pan, and dredge the shrimp in the flour, tapping off the excess. Heat 2 tablespoons of the oil in a large Dutch oven over medium-high heat, and add the shrimp. Cook, turning once, until seared on both sides, about a minute per side. Remove to a plate.

Add 2 more tablespoons oil to the pot. Season the scallops with ½ teaspoon salt. Dredge the scallops in flour, and brown on both sides, like the shrimp, about 1 minute per side. Remove to the plate with the shrimp.

Pour out any oil left in the pot, and wipe it clean with a paper towel. Over medium-high heat, add the remaining ¼ cup olive oil. When the oil is hot, add the garlic and thyme, and cook until sizzling, about 1 minute. Add the wine, lemon juice, and red pepper flakes, and bring to a simmer. Dump in the clams, and cover the pot. Simmer just until they begin to open, about 3 minutes. Add the mussels, season with the remaining ½ teaspoon salt, and cover again. Cook about 3 to 4 minutes more, and discard any that haven’t opened.

Add the shrimp, scallops, scallions, and parsley. Cook and toss just until the shrimp and scallops are heated through, about 3 minutes.

With a spider, transfer the seafood to a serving bowl, leaving the cooking juices behind. Bring the juices to a boil, and sprinkle in a tablespoon of the bread crumbs. Bring to a simmer, and cook until sauce is thickened, adding up to 1 tablespoon more bread crumbs if it is still too loose. Drizzle in a little olive oil, pour all of the juices over the seafood, and serve right away with crusty bread.