Beat unsalted butter, powdered sugar, vanilla and coconut extracts, salt, freeze dried mango powder, and heavy cream (or coconut milk) on low for about 30 seconds before increasing speed to medium high for 5 minutes.
Meanwhile, after cupcakes have cooled, add mango filling to them. If you have a cupcake corer, use it, but if not (I don't) make a hole in each cupcake using the wider opening of a piping tip.
Scoop about 2 teaspoons of cooled mango filling into the hole of each cupcake. Firmly pack it down, though it's okay if some of the filling spills over the top of the hole. You'll cover it with frosting anyhow.
If you have any mango puree remaining after filling your cupcakes, you can add a few tablespoons of that back into your frosting and mix it well before putting your frosting in a piping bag.