... like this video, "Very nice cat from the neighbourhood that visits me in the office every day" (https://www.youtube.com/watch?v=sLnC4fjSKdc). This cat just shows up every day around the same time to hang out with someone at work, and the only clue to where this cat comes from is, it must be a country where they use British spellings.

I have a brown and black mackerel tabby, and he does EXACTLY THIS with a stuffed dragon my mom's dog left behind when he came to stay. He will try to kill it one second, and then he'll start purring and start licking it as if it were a kitten the next. He carries it around the house, even back and forth between the water bowl and the litter box.

I would be interested to know what cats do when faced with a dead kitten in their environment. Are they triggered to try to revive it, or are they just clearing it away from public view?

I like (non purebred, of course, because fuck animal breeding) Maine Coon cats, myself. Had one that was a shelter rescue for a long time and he was kind of too smart for his own good and could be a hassle, but he was also just about the most fun cat to hang out with, really playful even as an adult, easy to carry around, and obsessed with water, which is a typical Maine Coon thing. He'd sit in the sink and wait for you to run it over his head.