I don't see a problem with having a beard.
it would be nice to see the undead use modified prosthetics for combat or something more specific.
Maybe metal details like a steel jaw.
Instead of tattoos, how about bone rune options?
Maybe, maybe it's able to change the size of bones or musculature.
Zombies and vampires are also undead.
Maybe elven zombies or dwarven zombies and so on...
A "Bearan" skeleton.
Instead of adding color to the eyes, adding a green or blue or red light looks better.