I have a cat on my desk right now. Got him neutered last week - he was back on my lap in less than a day
and he is a reformed feral
One thing I've been told by a lady who's an expert on ferals and strays (and runs the local cat shelter) is not to wait too long trying to befriend them. Her advice was to get them neutered first and work with them from there. She says that once they reach sexual maturity (which could be as early as 4-5 months in some cats), the may roam away and disappear. I was working with a couple of ferals here and she suggested to give it a week of trying to socialize them enough to get them in the carrier. If that doesn't work in a week, you need to get a humane trap and get them that way. With those two I managed to befriend them within a week (I guess they were only semi-feral), otherwise I was going to trap them.
Another thing, is if you live in a safe environment, I'm not sure it will be for the best to bring those kitties indoors. Feral cats can get confinement stress and be miserable indoors. Every cat is different of course, but with many ferals, you just can't get them to be as sociable as pet cats. And those cats belong in a supervised colony where they can get food, shelter and medical care. I wouldn't take them indoors or to a shelter, just keep looking after them.
Again, every case is different and I wouldn't presume telling you what to do with your cats based on your two posts here, but just wanted to bring up the point.This link
will take you to some of the best feral care websites out there if you're looking for more info, and of course there's always this board.
Thank you for helping those kitties!