I have fully painted all of the coffins.  I have been having trouble getting the doors to stay on and open with the bigger coffins, but the little coffins seem to be fine.  I used super glue for the hinges.  I also superglued some flat plastic hooks to the tops of the insides of the coffins to hang the characters from.  Some of the skeletons had the metal loops at the top of their heads oriented the wrong way, but that was an easy fix (I was worried the wires would come out of their heads if I messed with them too much).  I hung all the skeletons in their coffins and they all fit perfectly except the dog.  He is a little too snug, but it still works well enough.