Ahhh how sweet
As for people keeping jills and kits on their own, perhaps things have happened in the past. Maybe other jills and hobs have killed kits. I can't see that it's just a myth born out of nowhere....
However, I'm quite sure some will be fine. Nothing is set in stone.
Maybe, space plays a part. Rather than a crowded hutch, there's a good sized living accommodation, so all the ferrets can be in different areas if they choose.
Anyway, whatever the reason things have worked out fine, they're all looking fab, Stubby