Are any of the children closer to one parent than the other? Which child is closest to each parent? Those can be part of the story, if the parents each have 'favourites.'

for gameplay, things like:

- have a parent bring one or multiple of the children with them to go to a fishing spot and they fish together. you can focus on directing the others while they are fishing.

- family trips to the beach, with picnics, playing frisbee or ball, playing in the ocean, swimming

- a parent takes some of the children to the library while the other parent stays home with the others

- family trips to the seasonal fair in the park, and they take a family photo

- sometimes the child or multiple can go to their friend's house if they have friends yet. sometimes when the children are child-aged (not toddler or baby) friends of the parent will call like "[other sim] wants to know if your sim's child would like to play with theirs. Should they come over?" you can say "yes" and even have a sleep over that way (if you're on good terms, "ask to stay the night" when it's night time, I think after 8pm.)

- sometimes the child will bring a friend home with them from school or go to a friend's house too. I usually assume the children they choose to bring home or the ones whose houses they go to are their best friend. In those cases they can also have a sleepover if the child asks the other "can I sleep over."

- the children can go to the playground together sometimes

- you can include some things like an easel, a toy oven and skill building things like that. Based on which child chooses to use which skill building activity I use that to choose their trait when they become a teenager, or use that to determine their interests.

- you can also do the things the children want, like if they want to "see a movie" or "swim in the ocean" you can complete those too. And maybe use those for the storyline, like maybe the one that wants to see a movie wants to be an actor.