Today, when I came downstairs, Smoke was in the porch trying to eat frozen cat food. I opened the door and told him to wait, and I'd get him something fresh. I did, he did, and I sat there with him while he ate five ounces of cat food. While he was eating, I touched his back and he retreated outdoors. He came back in when I called him. While he resumed eating, I kneeled next to him and talked to him. He stopped at one point and rubbed his face on my knee. Maybe it was a sign of affection or maybe he just needed a napkin, I don't know.
I took it to be a sign of affection, or at least trust, so I touched his back again and he didn't withdraw. For a couple of minutes, he let me pet him full on, and it was clear that he was enjoying it, although there was no purring. When I tried touching the side of his face, which cats who truly trust you like a lot, he withdrew again, so I went back to petting him from the top of his head to the tip of his tail. He let me pet him with both hands on either of his sides, and seemed even to move so that I could reach him more easily.
He finished that can of food and resumed trying to eat the frozen stuff, so I promised him another can. I opened a 3 oz can, put that on a plate (I have learned that cats prefer plates to bowls; I think it's a whisker thing), although I tend to still refer to them as bowls, having fed cats in bowls for decades.
He finished that and stayed there, letting me pet him. I tried picking him up and, while he was trembling, he let me hold him. Kissing him on the top of the head was too much though, which is understandable since every cat I've ever had has acted like that was a weird thing to do. He wasn't comfortable being held long, but didn't leave when I set him down. I picked him up again and he seemed to be resisting it until I brought him up to the door window and he could see inside. He was fascinated in that because he can't view the window from the floor.
He didn't want me to hold him tightly, but seemed a little more comfortable with it than the first time. I had never tried picking him up before, and had only petted him once previously, and that wasn't for long.
Ella was on the stairs watching me holding him to the window, and she didn't look agitated, although I wouldn't be able to hear hissing from the closed door. After a bit of that, Smoke wanted back down. He ran outside, but then came right back in again. I opened the door a crack so that the two cats could sniff at one another, but that panicked Smoke, so I thought I'd leave that alone for now. He came back inside and started eating kibble.
I went inside to see what Ella's responses would be. Not only had I been petting him, but I had held him in my arms, she had witnessed that. On other occasions when I had fraternized with someone else's cat, Ella would hiss at me after detecting it on my hands or clothing, but she didn't hiss. I would have to change clothes and wash my hands before I could handle her after petting some other cats. She was clearly interested in the smells of that other cat, but she didn't hiss. When I put her down, she did her treat request, and I thought that if seeing me with the other cat resulted in treats for her, that might help, so I gave her treats.
She came back out and started sniffing around the door. Smoke was still there, so I picked Ella up so that she could see him through the window. She hissed once but it wasn't a very enthusiastic hiss; it was more like the kind of a hiss she would greet Bubba with after the serious anger over his presence had subsided. When Smoke noticed we were at the window, he looked up and Ella hissed again but again, it wasn't the kind of hiss that sounded like it was intended to be taken seriously.
Smoke finished eating, having consumed more than most two cats would have eaten in one sitting, and he left. Ella seems fine. I don't know how often these two cats had encountered one another when Ella was allowed to go outdoors, as I had only seen them together once, but they were sitting right next to one another then. Cats do have long memories, so maybe she does remember Smoke.
It looks like things are accelerating, though. Since he allowed me to pet and even to pick him up, and his world didn't come crashing down around him, I expect he'll be comfortable with me again.