In a mixer with the paddle attachment, combine the butter, chipotle peppers, 1 tablespoon of the adobo sauce and 1 tablespoon of the lime juice. Season with salt and pepper, then paddle the mixture until the ingredients are distributed evenly.
In a bowl, mix the sour cream with the remaining 1 tablespoon adobo sauce. Season with salt and pepper. Refrigerate until ready to use.
In a bowl, combine the shrimp, tequila, olive oil, minced cilantro and remaining 1 tablespoon lime juice. Season with salt and pepper.
Spread a heaping tablespoon of the butter mixture onto each lobster split. Put the lobster butter-side up on the grill, along with the shrimp. Grill the shrimp until just cooked through, about 3 minutes per side. Grill the lobster until the butter is melted and the meat is just heated through. Remove the lobster meat from the shells and chop into 3/4-inch pieces.
Grill the tortillas until warmed. Assemble the tacos by distributing the lobster and shrimp among the tortillas, then topping with the radishes, sliced avocado, Fresno chile slices, cilantro leaves and sour cream mixture. Serve with a lime wedge.