Preheat your oven to 350 degree F, and line a 12-count muffin tin with paper cupcake liners.
In the bowl of your stand mixer (with paddle attachment fixed), cream together the butter and sugar. Add each egg, one at a time, mixing completely after each addition. Add the vanilla extract, banana, and pineapple. Mix until incorporated. NOTE: A hand mixer works just fine for this step.
In a medium bowl, whisk together the flour, baking powder, cinnamon, and salt. Add the mixture to the wet ingredients, and mix on low until thoroughly combined. Stir in the coconut and walnuts.
Pour the batter into the muffin tin, and bake for 20 minutes or until an inserted toothpick comes out clean. Let cool completely on a wire rack before frosting.
For the frosting, cream together the cream cheese and butter in the bowl of your stand mixer. Add the confectioners' sugar and vanilla extract. Beat on low until just incorporated. Beat on high until smooth.
Frost the cupcakes and serve! Best served day of bake, but will keep for a few days in an airtight container in the fridge.