Susie, I read most of the pages and thank you for posting. I do not have any special recommendations on what to do, but I can share my story.
Our friends owned a farm house where two young feral cats would get fed. In about 5-8 years, they got a good relationship with them but somewhat distant. They were able to get the male cat neutered in this time. Put out food, eventually, got them to start using a litter box. Well our friends decided to sell their house in the country and could not take the cats. In the middle of winter. We get temps here that can go real low in the north, negative 20 with a windchill of -40 is the worst I can recall in my life.
Well, they move and say no one can take our cats. You have a hobby farm, would you be interested?
My wife and I were not looking but thought it is better than to let the critters go off on their own. The female who was 17-18 in our best understanding didn't last the winter outdoors. The male who we think is 12-13 did after a couple weeks (we even put heaters in our barn for the old gal...sad).
It got brutally cold, negative 12-15 degrees here without windchill for a few days straight. I told my wife if we see the male (cuz we would feed them) I was going to try to bring him indoors and put him in our basement if nothin' else.
I called him on a cold, cold, cold night and said come here boy, in a soft voice and he walked into our farmhouse kitchen, where it was warm. It took him 2-3 weeks before he would stop hiding on us, but he did use a litter box from day 1.
Fast forward to now, that cat is the biggest baby on the planet. He loves snuggling, actually too much, always following us walking or wants to be by us constantly or held. He is the most well behaved cat I have ever owned, having cats since I was a young kid. At night now, he likes to sleep in bed with us and snuggle. He is a talker and if we close the bedroom door, he justs stands outside it and cries. He is relaxing right now, in MY chair, not a care in the world. Very strong, muscular cat. This Tom Cat even figured out that human food is good. HaHa. Thank my wife for that one. Well, he likes treats, is a big baby, and is just the nicest cat.
He now tries to knead you if you stop petting him...
Hard to believe that 6-8 months ago he was a wild kitty and just passing from here to there.