eighteen 8-inch metal or wooden skewers (soaked in water for 30 minutes if wood)
Bring a large pot of salted water to a boil and prepare a bowl of ice water. Add the lobster tails to the boiling water and cook for 8 minutes, then remove to the ice water and let sit until chilled. Slice in half lengthwise, cutting through the shells, and devein.
Use 2 parallel skewers to thread 4 or 5 scallops, then repeat with the remaining scallops so you have 4 sets of double skewers. Repeat the same process with the shrimp. Thread all 4 lobster tail halves on two more skewers. Refrigerate until ready to grill.
Stir together the butter, paprika, chili powder, habanero and garlic in a medium pot, then season with salt and pepper. Place over low heat and heat until just melted.
Combine the capers, cilantro, mint, parsley, tarragon, thyme, chives and lemon zest in a medium bowl and mix. Add half to the melted butter and reserve the rest to garnish the platter.
Heat a grill to medium-high heat. Once the grill is hot, spray lightly with nonstick cooking spray or wipe down with paper towels dipped in canola oil.
Grill each lemon half, flesh-side down, until charred, 2 to 3 minutes per side. Set aside.
Place all the skewered seafood on a sheet tray and sprinkle both sides with salt and pepper; drizzle with olive oil. Place on the grill and cook with the lid open, flipping once, until the scallops and shrimp are opaque in the centers and the lobster tails are just lightly charred and warmed through, 2 to 4 minutes per side.
Remove all the grilled seafood to a large platter, then pour about half of the butter mixture over the top. Pour the remaining butter into 4 small ramekins and serve on the side for dipping. Garnish the platter with the remaining herb mixture and serve with the grilled lemon halves.