Coat 3 (9-inch) cakepans with cooking spray; dust lightly with flour. Set aside.
Beat butter and sugar at medium-high speed with an electric mixer until fluffy. Add egg yolks, one at a time, beating until blended after each addition. Beat in mashed sweet potatoes and next 6 ingredients, adding each ingredient one at a time. Add pecans and 3 cups flour, beating just until blended.
Beat egg whites in a separate bowl at high speed with an electric mixer until stiff peaks form; fold into batter. Spoon batter evenly into prepared pans.
Bake at 350° for 25 minutes or until wooden pick inserted in center comes out clean. Cool cakes in pans on wire racks 10 minutes; remove and cool completely on wire racks.
Spread Coconut Filling evenly between cake layers. Gradually pour about 1/2 cup Caramel Frosting on top of cake, spreading over top and sides with a small spatula. Place cake in refrigerator, and chill remaining Caramel Frosting 45 minutes. Pour another 1/2 cup Caramel Frosting on cake, spreading over top and sides. Chill cake and frosting 15 minutes. Repeat procedure with remaining frosting, 1/2 cup at a time. Store cake in refrigerator.