more then 7 sims in a house
And also read my post on the second page of comments on that mod, because it contains some lines that you should put in your UserStartup.cheat, in case you want to be able to move in sims from the neighborhood screen as well.
If you tried to add sims from the neighborhood screen, then it is no miracle that it didn't work, because no mod can ever help you there. You simply need the three lines in UserStartup.cheat for that.
The mod only works while you're playing a household. Every time you ask a sim to move in, or when a baby is about to be born, the game will test if there is room. My mod will then ALWAYS report that there is more than enough room to add sims. It just doesn't matter how many sims already live there, it will always work.
Besides... to "Stay in the house" is something different than to "Move in". Did you use the option "Propose.../Move in"??? Because that is what you need for a sim to become part of the family and live there.
You select a sim who already lives there, and let them interact with the visitor. Like this:
Hannah already lives in the house, and her friend Jack comes to visit. Now Hannah wants Jack to live with her, so you right-click Hannah, so she's your active sim. Then you left-click Jack, and select "Propose.../Move In". Hannah will then ask Jack to move in, and if Jack agrees, the SYSTEM will make him selectable and make him a real member of the household!!!
And do NOT make Jack selectable before you try this, because if he is selectable, Hannah does not get the option to propose moving in!