Alternative

I highly recommend to check out Dropkicker's HiPolify NPC Script for XEDIT which allows you to automatically generate patches for all NPCs in your load order.


Overview

Simple mod that changes human face meshes of all (at least I think I got them all) NPCs from the vanilla game to the HiPoly Faces Redux version.
This was mostly just an experimental mod to see if it would work, and how it would affect my fps (not very noticeable). Due to the high conflict potential it definitely requires patching on larger load orders and you should definitely check out Dropkicker's Script to make your life easier.
Light flagged ESP.

I'm terrible at taking screenshots (and even less capable of making proper comparison shots), but check out the Images tab of HiPoly Faces Redux if you need examples.


Requirements

HiPoly Faces Redux and its requirements, kinda obvious.
UFO4P - Forwarding essential changes.


Installation

Use a mod manager.
Due to the way NPCs are generated I do not recommend adding or removing this mid-playthrough.


Compatibility

This mod will conflict with pretty much every other mod that edits any NPC records, I recommend to create patches with xEdit or load other mods afterwards so their changes can take precedence (you will lose the changes of this mod for those NPCs then ofc).
I only used this mod in combination with the vanilla body and Enhanced Vanilla Bodies, I have not tested it with any other body type supported by HiPoly Faces Redux (although I assume it should work without issue).

Looted Power Armor Frames - patch for the few NPC changes of that mod in optional files.


Technical Details

Changes PNAM - Head Part record in every NPC from MaleHeadHuman/FemaleHeadHuman to MaleHeadHuman_HiPolyMod/FemaleHeadHuman_HiPolyMod.
This is the only change that needs to be forwarded when creating a patch.
This mod edits companions base records and it seems like that makes the companion features of HiPoly Faces Redux unnecessary.