Is there a way to recruit princesses, inquisitors, heretics and witches?

[Lonck]

i want to be able to recruit those units just for fun. Is that possible?

[Caesar Clivus]

I would assume by adding them to the recruiting pools for whatever building you want to recruit them from in export_descr_buildings.txt. Someone with more modding experience than me could give you more details though.

[uanime5]

Unfortunately there is no way to recruit these units, their appearence is hard coded.