Your story reminded me of a kitty we had 50 years ago. We bought a place in the country, and didn't know the owner left at least one cat. As winter came on, we heard a kitty, and then started seeing her. She was all black, and I think she was part Siamese. We kept her fed, and made a shelter outside. Spring came and we didn't see her all summer. Then fall, and she showed back up. We gained her trust. It took such a long time. I think we got her in the house, and she went bananas, and we put her right back out. The 3rd winter, she came in the house. The basement door was open and she ran down. We didn't see her all winter, just left food on the top step. When spring came she left. The next year, she came in and gave us a litter of kittens. She got a little tamer as time went on, but she was always wild. She'd let me pet her in the house. I tried to pet her outside once and I still have the scar on my arm. We called her Pilgrim. The relationships with the feral kitties are so unique and such a challenge. Totally worth it.