For the cake: Preheat the oven to 350 degrees. Grease and flour two 9-inch round cake pans.
Beat the egg whites until stiff. Set aside.
In a large bowl, cream together the butter, oil and granulated sugar until light and fluffy. Mix in the egg yolks, vanilla and coconut.
In a separate bowl, mix the flour, baking soda and baking powder. Alternate adding the buttermilk and dry ingredients to the wet ingredients. Mix until just combined, and then fold in the egg whites.
Pour evenly into the prepared pans and bake until a toothpick comes out clean, 20 to 25 minutes. Remove from the oven and allow to cool for 15 minutes. Then turn the cakes out onto cooling racks and allow to cool completely.
For the frosting: In a medium bowl, combine the cream cheese, butter, vanilla and powdered sugar. Beat until light and fluffy. Stir in the pecans and coconut.
To assemble: Cut each cake in half lengthwise so you are left with 4 layers. Spread the first layer with frosting and top with blueberries. Repeat the cake, frosting and blueberry layers until you have 4 layers of cake. Arrange more blueberries around the edge of each layer for structure.
Cream cheese frosting will soften at room temperature, so refrigerate if you won't use it right away.