I made a test version of NPC transformation.

PSQ3.2.9T.7z
Unfortunately the appearance change of NPC is not as good as PC. So I am late for the delay and I am very sorry.
Also, this is just registering NPC as a succubus and pressing it with a transformation hotkey. I also wanted to add many other things, but I can not do it because I am rebuilding the Skyrim environment from around the end of 2016.

Usage

Overriding to the previous version, aim the NPC to cross hair, press the Get NPC key of SexLab and set it like that from PSQ menu "Page_ 11".

The setting elements are roughly the same as those of the player.

Armor and Body are the same as those of the player.

I will repeat but for the moment just the appearance will change and nothing else will change.
Also, I can not change so much in the future because the thing that NPC can do is known so much.