Preheat oven to 400 degrees F (200 degrees C).

Fill a large pot with 2 inches of water and bring to a boil. Submerge lobsters head-first into the boiling water; cover and steam until bright red, about 15 minutes. Remove from the pot and submerge in cold water.

Heat 2 tablespoons butter in a skillet over medium heat. Add scallops, shallot, and garlic. Cook and stir until shallot is tender and scallops are partially cooked, about 3 minutes. Cool slightly, about 1 minute. Fold in cracker crumbs and parsley to make a loose stuffing.

Place lobsters on a work surface. Crack claws on one side. Split underside of body with kitchen scissors. Remove tomalley (liver), roe (eggs), sac (behind eyes), and intestinal vein. Split tail open and bend shell back underneath to lie flat to make ample room for stuffing.

Place lobsters in a jelly roll pan with backs facing down. Baste with the about 3 tablespoons melted butter, including the shell area. Stuff body cavities and tails with filling. Drizzle the remaining butter over all.

Bake in the preheated oven until filling is golden brown, about 20 minutes.