Describing a city as a province level administrative unit is just describing how it fits within China's government structure. Basically that said city will report directly to the federal government as opposed to an intermediary body. What it doesn't describe is how important this city is, and when it comes to naming ships, importance and symbolic value are paramount.
I'd say that any future carriers will be first named after costal provinces. The ones without ships assigned are Hainan, Guangdong, Zhejiang, Jiangsu, Hebei, and Guangxi. If there are any more carriers beyond this, the PLAN will start going after the inland provinces and autonomous regions. My guess is that the province-level cities will be assigned to cruiser-sized vessels should China decide to go that route.
I don't think this is true at all. Hong Kong is more important to China than it was in 2019, and it's definitely in China's interests to treat everyone as one big happy family. Besides, Hong Kong is far enough back in line that it's possible that nothing will be named for it for the next 20 years. By then, I doubt many people will object to Hong Kong any more.