Hmmm, I Suggest (This Might be Preety Hard...) That the ghost should be holding something corresponding to the class the player uses. here are tha list i suggest :) (u may put it either left or right hand...) (Also U May Change Whatever item to the List). :

Scout: A Fried Chicken Tramp
Soldier: A Mug (Maybe Add Some Hot Chocolate or Coffe?)
Pyro: A Ballon which is shape is of the Ballonicorn
Demo: A Beer
Heavy: A Bullet
Engineer: A Wrench (Normal Wrench)
Medic: A Bottle Of medicine (Maybe Pills?)
Sniper: A Jarate (or A Self Aware Beauty Mark, Whichever The player Uses Either item)
Spy: A Mini Sapper.

So Thats All, ;D :) Wish This will be on the game one day....one day....;D
Note: Just A Suggestion!