Combine 1/4 olive oil, 1/4 cup of butter, garlic, lime juice, vinegar, salt, and pepper in a blender; blend until marinade is smooth.
Place squid and prawns into a bowl, pour in marinade, and stir until well coated. Cover bowl with plastic wrap and refrigerate for 30 minutes.
Heat remaining 1/4 cup olive oil and 1/4 cup butter in a skillet over medium heat and cook chile until fragrant, 1 to 2 minutes. Add squid and shrimp; cook and stir until evenly browned, 10 to 15 minutes per side.