Cathar is the only heresy that unlocks Absolute Cognatic. I was actually aiming to get it to allow for female council members but then I found out that the Cathar faith has no pope. Without a pope, I can't excommunicate bad vassals and imprison/execute them. Do Cathar males dislike female rulers?
Messalian also unlocks Absolute Cognatic, as well as female council and priests (though it also has no Pope). It's Extra Heresy at its finest.
Never played as Cathar, sorry. I think the female ruler penalty might be universal, I've never investigated it.
Messalians have the added mechanic of Divine Blood, like Zoroastrians... but no concubines, so you are forced into having inbred heirs.
Anyway,
you know what time it is. This is the last one, since the release is in 7 days.
There are special events if you control the silk road. For instance, a chinese(!) emperor might send a governor to help you administrate your routes.
There are also various events to tell you what your heir-turned-mercenary is up to. From the related screenshot, it seems they can convert to other religions, as shown by the heir becoming Zunist. Other things that might happen is increasing the level of the military education trait, having bastards and so on. I'm guessing it will depend on traits, with diligent mercenaries using the cash to improve their company, lustful and/or hedonistic having bastards and squandering the cash, and, I think, cynical one converting to other religions.
As a nomad, you'll also be able to adopt a personal warhorse, which I assume works like the hunting dog.
This... was a pretty weak dev diary, actually.
There was also this line
Oh! And I might actually have heard legends about certain altaic families behaving in odd ways lately… with hideous faces and beast-like behavior.
but unless it is about Secret Bears, I don't know what it might be about.