There are beastman mods that let minor beastman factions settle and in my latest campaign, they did settle quite reliably and did not enforce many bloodgrounds.
If you have an idea for a Mod that makes Bloodgrounds more complex with settlement options like only allowing your allies to settle, then please let me know as I would be interested.
For reducing corruption for your scenario you do have that mod to work with you commented on.

+rep always one of the cooler people to talk our fav horror franchises with

hay want to fight the bosses