Hair Stylist NPC
It would be pretty handy to have a way to change heads and hair color that is similar to the npcs that exist already for tattoos.
It could have a small fee, like the tattoo npc. If the potential to freely change heads and hair colors is seen as problematic, there may be a small cooldown, at least at first, while it is tested.
Personally I have seen this kind of free ability on other servers for both NWN:EE and NWN2 being freely available and not causing any issue whatsoever, so I am extremely skeptic about it causing any problem here either.
On the other hand there is the clear benefit of seeing more heads used, especially the ones that have some attire parts on them, like bandanas, helmets, etc. that right now are seldom used, precisely because of the fact that they are then difficult to remove, if, say, the character wants to roleplay removing the helmet.
Last but not least, changing the head model, that is changing the hair style should not make the character unable to be recognized. As when we change hairstyle we are usually recognized in real life without much issues, if not for a few seconds, at most, the same should be valid in game.
P.S.
As an ancillary suggestion, it could be evaluated the possibility to have a few head slots, that one can use, so that one can have a look with bandana or without, or with long hair and tied hair, and so on. I think it would be another reasonable thing to have.