All of these mods (or part like textures) can be used as resource for your mod without permission but it must remain free.
Here are examples of my wip /!\ +18 spoiler /!\
Boby painting using overlays (like body tatoo overlays with bgem files), face painting using human race alteration like seen in a tutorial here on laverslab By Frayja
(Thanks you Frayja).
Facials are not compatible with mods that edits humanrace too like looksmenu compendium Solved