OK fair enough. For myself its all meta, but I know there will be others who want to preserve a sense of consequence for the initial choices made, and to have everything that happens afterward be consistent within some kind of in-game reality or rationalization.
In that case they can do the split approach and keep it totally in-game.
1. For Make-up a looking glass icon in Char Sheet tab accessible at any point, no cost in gold.
2. Hair Styling (cuts/dyes) a specialty vender/market or a camp follower who is easy to access. Maybe Shadowheart helps you bleach your bangs at camp? Lol whatever works. Small cost in gold for that.
3. Tattoos (and Magical tattoo removal) provided by Nettie or Abdirak, for a moderate cost in gold.
4. For changes to major stuff like heads, skin color, eyecolor, phenotype, sex, voice, and the like, some sort of wizard/witch, who sells the requisite artifact or potion to unlock those aspects of the appearance tab, for a large cost in gold.
That would cover everything and provide a narrative rationale for each, provided it wasn't a total pain to access the various locations where such NPCs might be found.
That sounds good. It is true that I would also like to be able to completely change my appearance, voice or name at any time (preferably at no cost), but this idea seems more logical from the point of view of the game world. In the case of a name, this could be resolved either by the possibility of changing it at any time (are there documents in the D&D world?) Or going to some member of the thieves guild or a similar shady person and changing the character's name for at average cost in gold.