I am certain this is an amateur hour question for an actual modder, but I was wondering how I would go about modding just the character I'm playing? As opposed to adding mods that would change all the NPCs as well?

For example if I wanted to add a custom skin, hair or eye mod, what is the procedure to have those mods only effect the player character?

Any assistance would be greatly appreciated. Thank you.

custom races are only for the player,

they don't show up anywhere else in the game.

race menu, chargen, eye mods, etc

idk how the game handles it specifically, but i've used all of them, and haven't seen wildly differnet npc's decked out with the new stuff,

I do know replacers will show up, but non replacers shouldn't be used afaik. i guess it depends on the mod