I love seeing new modders hit the scene and add more content! If there's anything that I can do to help your friend, just let me know! I think that'd be a fun addition. The marriage concept has been mentioned and I had something similar slated for a future version but if he makes it and we work out some compatibility, I'd be happy to see it!
The Independent Actors idea (regarding the kids idea) with "squads" that can be sent out is something that is very likely going to be happening in the Town Expanded update building off of the persistent NPCs format. Its tricky to get to play nicely, but very doable. Good luck to him and I look forward to seeing it!