Whisk together pudding mix, milk, and coconut extract until thickened. Stir in food coloring, then pineapple and 1/4 cup coconut. Fold in 3 cups thawed whipped topping. Spread in prepared shortbread crumb crust. Cover; freeze 6 hours or overnight. Before serving, spread with 2 cups thawed whipped topping and 1/4 cup coconut.