I have watched countless videos and looked through forums, but I find, those who have the same amount of mods as I, are not finding direct answers. Once you change the MC Setting mentioned above, what happens exacty when you try to MC > Add Sim or do an Instant Baby or Pollinate? So, starting with MC then since this is the simplest. Doesn't actually allow or disallow anytihng about household size on its own.
PortraitPanel: Opens up more slots on the portrait panel on the left side of the screen. SP has its own household cap that can be found under Household (Caste, Town) Options
StoryProgression: Allows inactive households to overstuff themselves and to hold together if an overstuffed household is switched out of to make a different household active. Mover: Unlocks in-game moves using the phone/computer into and away from overstuffed households, as well as moves and splits using Edit Town. Woohooer: Potentially unlocks Risky and TryForBaby when a household is full or already overstuffed. MC Integration: With the setting above, allows up to 10 sims in Create a Household (CAH). This only applies to MC commands specifically, like Add Sim, Pollinate, Instant Baby, Adopt.
MC: NRaas > MC > Settings > Allow More Than Eight > True Each of the mods involved with lifting Greater Than Eight restrictions does so in very different ways.