In a small bowl, combine the boiling water, cocoa and coffee. Stir until cocoa is dissolved; set aside.
In a large bowl, cream butter and sugar until light and fluffy.
Add eggs, one at a time, beating well after each addition. Beat in cocoa mixture and vanilla. Combine the flour, baking soda, salt and baking powder; add to creamed mixture just until moistened.
Fill paper-lined muffin cups three-fourths full. Bake at 375° for 18-20 minutes or until a toothpick inserted in cupcake comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely.
Combine hot water and salt; stir until dissolved. Cool. In a large bowl, beat the marshmallow creme, shortening and vanilla until light and fluffy. Gradually add the confectioners sugar and salt mixture. Beat until fluffy.
Cut a small hole in the corner of a pastry or plastic bag; insert a very small tip. Fill with marshmallow filling. Push the tip through the top to fill each cupcake.
In a large bowl, beat the cream cheese, butter and vanilla until fluffy. Add confectioners sugar; beat until smooth. Frost cupcakes. Decorate with sprinkles and candies as desired. Refrigerate leftovers. Yield: 1-1/2 dozen.