A documentary team in the UK put a bunch of boys in a house for a weekend and filmed them. No adults. Just middle school boys and all strangers before the experiment. They repeated it with girls. Both are up on YouTube in full.

Middle schoolers have underdeveloped brains so its fairly predictable that both groups get up to some stupid shit but its the little differences that are interesting.

As for mixing boys and girls, I'm a cynic so if they were over the age of 14 I'd guess it wouldn't go very well for the girls, especially if it was a plane crash on an island and not a single weekend in a house with a clear escape time and cameras rolling. Under 14, its hard to say.

Go to your local author guild or library and ask about local indie authors. You can probably inquire through Facebook or their email. Chances are there are dozens you haven't heard of and at least half are publishing quality work. You will find more than one hidden gem among them.

I do not recommend going on an open "self published" or "indie authors" group because you'll get a higher percentage of garbage. The ones who are doing readings and workshops with local establishments or who have their books in the local library, are more likely to be edited and good quality writing.

A modified baby gate at the foot of the stairs?

Can they be relegated to the basement?