I once had a very hard look at whether the activity in this song would be possible - and I mean the use of more human material than just the finger bone. The conclusion was that bone used in any part of the instrument would be too brittle to withstand any kind of string tension - and this included the pegs.

I think using white paint of some kind would be the best solution.

So far I have found that only some minor Buddhist sects made instruments out of dead people and it had something to do with letting the dead speak (but I could be wrong there).

Cheers
Sarah