Preheat oven to 375 degrees. In a large bowl, beat together butter and sugar with beater until fluffy. Add molasses and eggs; beat until well blended. In medium bowl, combine flours, oats, baking soda, baking powder, cinnamon, and salt.
With a wooden spoon, stir flour mixture into butter mixture alternately with buttermilk, beginning and ending with flour mixture. Fold in chopped starfruit, coconut, and orange peel. Divide batter into paper-lined muffin cups, filling each two-thirds full.
Top each cup with one starfruit slice. Bake muffins 20 to 25 minutes or until they're golden brown and spring back when pressed lightly. Cool on rack 5 minutes; remove from pan and dust lightly with confectioners sugar.