I agree with everything you stated - we should be granted the ability to loot or kill unconscious NPC. This is a must! About the changing of its clothes - this sounds funny, but it should be NPC stats dependend if it will be killed by his own people or not. After all, they know the person, he speaks their language, so if NPC manage to speak quickly and explain the situation then it shouldn’t be killed by his own. Except that some trigger happy NPC may see the dressed-up NPC and shoot it with a bow from away, before the last has a chance to expain himself.
Another thing, which is close to common sense. We SHOULD be able to buy a rope and use it to tie up and gag any unconscious NPC. Then drag them to some secluded places and hide them there. This way we won’t need to kill them, but we won’t risk them to wake up and alert others. Makes so much more fun and realism if you are a pacifist person and want to play Deliverance as a sneaky character who doesn’t kill anyone without last resort. @warhorse, what do you say?