Preheat the oven to 350 degrees F. Line 3 (6-cup) muffin pans with cupcake liners.
Frosting: Put the chocolate chips and shortening in a medium microwavable bowl. Microwave on high, stirring halfway between cooking time, until the chocolate is melted, about 40 to 50 seconds. Stir until smooth. With an electric mixer on low speed, beat the cream cheese in a medium bowl until smooth, about 1 minute. Beat in the melted chocolate, orange juice, vanilla, and salt until blended. With the mixer on low speed, beat in the confectioners' sugar, 1/2 cup at a time, until smooth, about 2 to 3 minutes. Cover with plastic wrap and set aside.
Cupcakes: Whisk together the flour, baking powder, and salt in a medium bowl. With an electric mixer on high speed, beat the butter, sugar, vanilla, and salt in a large bowl until light and fluffy. Add the egg and egg yolks, 1 at time, beating well after each addition. With the mixer on medium speed, beat in the sour cream, zest, and juice until blended. Add the flour mixture on low speed, and beat until just blended.
Fill each muffin cup 2/3 full with the batter. Bake until a toothpick inserted into the center comes out clean, 17 to 20 minutes. Let cool in the pan on a rack for 10 minutes. Remove the cupcakes from the pan and let cool completely on a rack.
With a small metal spatula, spread the frosting over the tops of the cooled cupcakes; use assorted fruit and candies to decorate the cupcakes.