It looks like there is a way, i think.. according to wsturm's post about How to Change costume, face, body. The paladin/dk models are located under inner armor, soo... through that reasoning, you should replace your inner armor with the succubus. and with that i think thats why his face was smasshed.
It even says it in the post -.-
EDIT: Confirmed that you can use the Succubus Model by switching the files with innerarmor files, however the face and hair still remains a problem.
Idk how to qoute e.e;
As MetaLoid said->
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It's quite simple to do, but if you have never done it it's probably complicated as hell xD Please remember to replace the 2 files in the bin folder that's available in the download with the ones in your en-us folder.
To get the Succubus model working as innerarmor, you need to:
1)Download the files in the first page and locate the transformation files that turn you into Suc (Succubus_Transformation2/broken/data/models/player/darkknight). This also works for the "full" version of the Succubus (the one with no breakoffs), just choose the full folder instead of the broken folder and follow the steps from above.
2) Now with these 5 files (there's 5 for females, 5 for males), change the name of these files into whatever your inner armor is called. For instance, to change Evie's basic inner armor to the Succubus model, rename all the "female_darkknight" files into "evy_inner_free". So in the end you should have "evy_inner_free.dx80", "evy_inner_free.dx90", "evy_inner_free.mdl", "evy_inner_free.vvd" and ""evy_inner_free.sw". Now here's the one tricky part, you MUST CHANGE THE SW you see there into "phy" OR THIS WON'T WORK
3) Last step, take these 5 files and put them in your (en-US/data/models/player/evy) If you dont have any of these folders, go make a one and name the folder as whatever you were missing
PLEASE NOTE: You may have to completely take the data folder that was downloaded in the first page and merge it with your current data folder to get this to work, I haven't tried this mod without merging these files.
And @
Gecko yeah there are files associated with head and hair, but the main issue is I CAN mod it into something else, such as a Lann's face with his hair, but not completely invisible =/ Still trying some other ways atm.