Melt butter in a large skillet. Add coconut and 1/2 cup pecans; cook until golden, stirring frequently. Set mixture aside and let cool slightly.
Combine cream cheese and sweetened condensed milk; beat at medium speed of an electric mixer until smooth. Fold in whipped topping.
Layer 1/4 of cream cheese mixture in each pastry shell. Drizzle 1/4 of caramel topping over each pie. Sprinkle 1/4 coconut mixture evenly over each pie.
Repeat layers with remaining cream cheese mixture, caramel topping, and coconut mixture. Cover and freeze pies at least 8 hours.
Let frozen pies stand at room temperature 5 minutes before slicing. Garnish, if desired.