Preheat oven to 350*F (175*C). Grease a a 13 x 9 x 2- inch baking pan. Set aside.
Lay tortillas on a flat working surface. In the middle of each tortilla place an equal amount of cheese (using 2 cups), crab, and shrimp. Fold the sides in and roll the tortilla to form an enchilada. Place enchilada seam-side down in prepared baking pan. Repeat with remaining tortillas. Pour green enchilada sauce over the enchiladas, covering completely. Sprinkle with the remaining 1 cup cheese.
Cover with aluminum foil and bake for 30 minutes. Uncover and cook an additional 15 minutes.
Serve garnished with a dollop of sour cream, green onions and cilantro. Pass the lime wedges for an additional taste sensation.