Options with Toddler when both parents are working?

At those who add the teens to families @EnkiSchmidt and @pixiejuice.
How do you get them back to their real families with the least play disruption? Do you have to go to managed worlds or do you use homeless teens? I like this option but I'd want to not have to exit the home later to make things right.
I have played with live-in staff before and have pretended one was an Au pair. Just wondering what I'm missing. I'm using cheats more and more and if it's simple I might go for it.