I hope they start using the same rules for custom as premade. I also hope that a faction editor will be back.

It seemed that features were enabled and disabled throughout Beta, so it shouldn't reflect what's going to be in the game.

But, I have no inside knowledge.

I have only ever used a custom sovereign - 15 WIS, the rest in CHA, and only the Summoning spellbook.  Get all the NPCs you can, keep them with you, give everyone a Demon Sword when you can afford it (but balance with building settlements up) then Large Wood Shield then Medical Pack - upgrading to Great Scythe and Large Master Metal Shield when available.  Use money from monster fights (mostly) and questing to fund initially, until your settlements are bringing you plenty of income - at which point you are likely ready to betaking over the NPC settlements.  Otherwise, just be sure to watch your food and be sure to have at least two units to guard with before moving on to rampage at the next settlement.  Don't bother with metal for your units unless you have lots coming in.

We'll see how it works in the release version.