As I mention in the video, I'm sure there is a more elegant way to do this, but I was unable to get a blank mod with dependencies working properly, whereas this way does. There are one or two weird bugs, but nothing harmful or too annoying.

Idiot-Proof Video Tutorial:
https://www.youtube.com/watch?v=WhErycQxHmM

Resources:
Full Skill / Ability / Talent list including in-code IDs
Templates for each basic class type
Visuals for all henchmen preset values

Guide:
* Create the path Divinity - Original Sin\Mods\Main\CharacterCreation\HenchManPresets\
* Create a .LSX file in this folder, name it anything you want. If you cannot find your henchman in game, rename it to something different and try again.
* Copy/paste the contents of the template you wish to use into it.
* Edit/Add/Change anything you wish using the provided in-game IDs.
* The picture of all the presets shows what the result is for each value from 0 to 16, for all entries (hair colour, head type, etc).
* The in game portrait corresponds to the 'Icon' entry.
* Save the file, and load your game. This is retroactive, and files can be deleted after you have recruited henchmen.

Known Bugs:
* Appearance for your henchman will be incorrect when you first load a save, you must warp somewhere that forces the game to load a map/level. Once you do, it will be properly reset. This happens every time you save and load. (Larian pls fix)
* The henchman list can sometimes get stuck or bug out in other ways. Change the filename of your .LSX until the henchman you want shows up.
* Your first 2 henchman you hire will have regular stat allocation, after that they receive less than normal. Pay attention to the number of Attribute points your henchman have, and adjust to your liking.