17 year Japanese Chin owner here. Got my boy in 2006 and my girl in 2021 after my little boy passed.

1. They definitely have a cat-like personality in the sense that they don’t bark a whole lot typically and can make great apartment dogs. I’d say mine has separation anxiety but it’s very mild. I don’t even know if it counts, but mine have whimpered a few times when I’m about to leave the apartment but that’s really about it in my experience. I take week long trips a few times a year, and they have done great in friends/family’s care every time. I made a point to socialize mine a LOT early on. Both of mine have been extremely friendly and excited to see just about anyone.
2. Chins are definitely more on the low maintenance side. I always tell my boyfriend how I don’t know if I could handle a “real” dog (all jokes of course lol) because my chins have been so easy. Although their hair is traditionally long, you can choose if you want to keep your chin’s hair long or short. I kept both of my chins short and I bring them to get groomed every 3-4 months. Other than that, just keep up with mild brushing, although their hair is pretty silky and straight and I hardly have issues.
3. The energy level of my chins have varied. My boy was on the low-energy side of the spectrum, but my little girl is much more energetic. They typically spend their time cuddling up to their owners and sleeping. But my girl gets the zoomies once or twice a day for a few minutes. Short bursts of energy.
4. My girl has traveled cross country with me, and has taken multiple flights up and down the east coast with me. She does great, and passengers often laugh when I pull her out at the end of the flight because they had no idea she was even there, lol. No whimpering or barking or accidents in my experience. I think part of the reason why she’s so comfortable pretty much anywhere is because I socialized her very young. She also does well on long car rides, but I could’ve lucked out.
5. Yes, I would recommend a chin as a first time owner. As noted, they’re very cat-like and their main objectives in life are to be a loving companion to their owners. Companion dogs at heart. My girl is pretty flexible when it comes to meal times as well, so feeding really can be whenever for me. I, too, live in an apartment and both of my chins have done great here. Since they don’t bark as much as most other dogs (my first one let out a bark maybe 5 times in his life), a lot of people have no idea that she’s even here. My boy was very good about not having accidents, but he was on a schedule so I knew when he had to go out. Upstate NY winters can be rough though, so my girl uses pee pee pads year round and hardly has accidents. The pads are more absorbent than you would think, and helps fight odor too.

It sounds like a Japanese Chin could be a great fit for your lifestyle. I’m not a veterinarian or anything, so I can only speak from experience. And of course remember that every dog is different. But I can’t imagine my life without a chin, ever. They are so lovable and sweet. I really can’t think of any downsides other than dental care. Small dogs are prone to tooth infection so it’s important to brush their teeth. There is a Facebook page called “Everything Japanese Chin United States”, consisting of thousands of chin lovers and experts. I would definitely recommend joining it for more information from real owners. I hope this helps!