I seem to have found a bug or maybe 2 relating to Neutral NPC settlements.

In my current game I have conquered three such NPC settlements the snathi, the poplar and the ironeers? at any rate i beat the settlements, then killed the sovereigns that were stood outside (taking the town before ending the faction).  However the settlements do not level up like other settlements, which they blatantly should.

"settlement will level up in 0 population" is all it says and they still list in the settlement info as Neutral settlements which they aren't.

Also the second thing is I remember in Frogboys video some time back he pointed out a neutral town stating it had an ogre village he would love as then he'd be able to train them (he was playing a kingdom at the time) but that he didn't want to take over the settltment as he was currently trading with it.  Well all three of my conquered Neutral NPC settlements have ogre villages yet I cannot utilise them as it says ogre villages cannot be developed by my faction.  Surely this is an error or all neutral settlements are only of use to the enemy which is uneven not to mention it also contradicts what was implied in said video i mentioned.