I wanted each of them to be recognizable on the tabletop to avoid confusion, so I painted each of the four with a different colored coat (so a player can say "I attack the one with the brown coat, not the one in the green coat"). Flesh is Pale Flesh washed with very dilute black ink to give it a sickly look. Mouth is Blood Red, eye sockets are completely black. The inner coat is Blood Red, outer coat is black drybrushed with Woodland Brown + Desert Gold (just to give it a bit of yellow zing, true brown would be a little boring). Pants are gray, coat buttons are silver metallic.