Combine cracker crumbs, basil, oregano, and tarragon in a large bowl.
Insert a knife about 3/4 of the way through the back of 1 shrimp; split nearly all the way down the center of the body. Open shrimp like a book. Repeat with 1/2 the shrimp.
Preheat oven to 350 degrees F (175 degrees C).
Melt butter in a skillet over medium heat. Add remaining shrimp and scallops; cook until nearly opaque and lightly browned, 3 to 4 minutes. Dice and add to the cracker mixture. Add clam juice and diced clams. Mix stuffing well.
Split lobsters all the way down the middle; clean the insides. Lay flat on a baking pan. Fill with the stuffing. Use remaining stuffing to stuff the butterflied shrimp. Squeeze lemon juice over the lobsters and shrimp.
Bake in the preheated oven until lobster and shrimp meat is opaque, 35 to 40 minutes.