So, because of very specific reasons, I'm trying to alter the vanilla vampire lord race, to wear a beast like helmet to hide the head, and a cape to hide any tails or lack of tails along with a robe and stuff, so it'd be a less jarring form for a khajiit or argonian to transform into. The idea is, said helmet and cape won't make it too hard to imagine a human orc or elf underneath, but it would also be far less jarring for an argonian or khajiit to turn into, because then your character doesn't magically have an exposed tail lacking fur lacking scale lacking body- and it's easier to imagine your character more or less the same underneath... While STILL allowing the tailless furless scaleless vampire lords to not look too beast like either.

This is just an experiment no guarantees, though I hope I can get something like this working. The reason behind this being, that making beast race specific vampire lords, is simply way too complicated- if NOT OUTRIGHT IMPOSSIBLE, so this seems to be the best compromise. I'm sorry, but I just cannot stand the thought of my khajiit turning into this VISIBLY tailless furless thing, and I bet many khajiit/argonian players feel similarly.

This whole idea is partially inspired by the mod Vampire Lord Armor, but is intended mainly for players who play as races with beast shaped skulls, and tails, scales, or fur. (And yes I have no choice but to alter vanilla things, but then, not many mods alter the appearance of the vampire lord anyways). (Though maybe people who play as humans elves or other tailless races would like it too).

The problem is this, so I'm using copies of vanilla meshes as my base for this... For some reason both Femaleheadkhajiit.nif and Maleheadkhajiit.nif work fine as the head, it was relatively easy to make a vampire lord that looks exactly like a khajiit... However, when I changed that to werewolfskull.nif all of a sudden it doesn't work- as in, isn't visible at all. In SPITE of the fact that it appeared on the model preview, and is also ticked Valid Races None+playable with none of the settings being any different.

How exactly would I go about turning this werewolf skull mesh into a full head covering HeadPart? I've seen Creation Kit guides on custom races, but NOTHING on how to repurpose armor, or misc parts into being head parts.

Are there any guides or anything on this specific type of thing?

Isn't the werewolf skull nif a clutter item? My experience with clutter things and the like is that if you make them into an armor piece (don't know about headpart though) then the item just keeps to the ground and isn't at all in the height of the head or wherever you'd like it to be. If the same is true for headparts, then I think you would need to edit the vampire lord mesh in a program like Blender or 3DS Max.