In a deep bowl, combine the breadcrumbs, coconut flakes, and 1/4 cup of cornstarch and set aside.
In a small mixing bowl, combine the piña colada mix, powdered sugar, and rum and set aside.
Place the remaining 1/2 cup cornstarch in a separate bowl.
In a deep fryer or heavy-bottomed pot, heat the vegetable oil to 375°F.
Coat the shrimp twice as follows: First, dredge the shrimp in cornstarch, dunk in the piña colada mix, and then dust in coconut breadcrumb mixture. Then, for the second coating, dunk the shrimp back in the piña colada mix followed by the coconut breadcrumb mixture.
Place the prepared shrimp carefully into the hot oil and fry until golden brown. Remove from the fryer and drain.
Serve with Red Lobster piña colada coconut shrimp sauce.