Hello, Neighborhood stories don’t have the feature which you mention. It can’t split and move in NPCs with other households. Also they can’t marry each other, they only allowed to divorce. NS respects gender choice, in fact they broke the romance setting as they fixed it so that gender preference got respected. I have formed romance options on with more as one single household and none of these singles formed a romance in over 12 Sim weeks with NS.
All other settings work well but you really need to adjust all settings. If you just let it run wild then you end up with a household full of horses/pets/children, which can a problem if you play with aging off for NPCs. Of course this only my experience in a vanilla game. I don’t use mods.
How then are these households being manipulated? I have experienced this with and without mods. Without mods everything in my original post happened. There are no other settings to set as I opt to disable autonomy, various social settings, etc.
I just revisited the Bugs Forum and searched for posts about Neighborhood Stories. There are several comments about babies being born, NPCs moving in, etc.
Ex.
https://forums.ea.com/idea/the-sims-4-bug-reports-en/neighborhood-stories-babies-in-npcs-household-with-settings-turned-off/12890992
