I think the point the previous poster was trying to make is that people have wildly different personalities, and that any observation with a sample size of 2 is basically useless to draw any conclusions from.

I'll also add that different people respond very different to things; maybe for some babies sleep training might have long-term effects, and for some it doesn't. Certainly if I look at my own shitty childhood, me and my brother responded quite differently. He was affected much less than I was.

Sort of. We initially fed our cat on demand, but at some point switched to feeding it at set times during the day. The cat adjusted to that, and suddenly all his daily activities - including playing and sleeping - started following a consistent schedule.

Not the OP and not sleep training, no need for that, but I did manage to poopy-train our cat, meaning he only takes a poo when we are awake. The same goes for when we are eating, he's not taking any poo during those times, either.

Pretty smart cat, if you ask me, he also managed to teach our dog to play certain kind of games between the two of them.

That's not necessary. Cats are expert sleepers!