Re: Adding tame kitten to feral cat household
IMO, if you put a socialized kitten outside a home setting and if the current colony of feral cats accepts him...there is a more than excellent chance this kitten will turn feral simply by following the lead of the established cats around him and your friend will *not* have the friendly kitten they wanted.
I think the young kitten would need to form a close bond with his people before they put him outside, so he knows to come to them and their home for his food/affection, just as *you* are doing with your own kittens. I am sorry, but unless they are willing to put in EQUAL amounts of time/effort exactly the way you are doing, they will probably *not* have good results with this kitten and I would not let them have one I had worked so hard to give the opportunity of a better life to, only to have it wind up in worse circumstances (feral, semi-feral or reluctant to approach people to experience the joys of human contact/affection). Granted, this kitten and circumstances may work out just fine, but for myself, I do not think I would chance it.
Best of luck to all involved,