1Mix cracker crumbs, coconut, cocoa and granulated sugar in medium bowl. Stir in 1/2 cup butter and the water. Press in ungreased square pan, 9x9x2 inches. Refrigerate while preparing topping.
2Mix remaining ingredients except candy decorations. (If necessary, stir in additional 1 to 2 teaspoons milk until spreadable.) Spread over layer in pan. Refrigerate 1 hour. Cut into 6 rows by 6 rows. Decorate with candy decorations. Store loosely covered in refrigerator.