If you want to build a China-only consumer product from scratch this is likely impossible as a foreign entity. Some specific industries will be laxer. But most pop consumer Internet is off-limits .
If you're introducing a somewhat established product and just want to broaden your customer base, then there are ways. But again super tough. Like the article you linked mentioned, many Chinese join venture schemes are just conduits for IP theft.
Generally my best guidance is to be very careful about risking any money in China. (lost quite a bit myself)
There's no publicly available information as to how YC China is structured legally. But they mentioned it's going to be China-first, investing on Chinese terms in Chinese companies. So likely the accelerator operation is going to be like any other in China. The creative part is how YC can maintain ownership over this structure.
 And despite what some will try to tell you, as an individual you also cannot own or hold stock in plain a domestic company. And all the crazy workarounds only start making sense once you're already very successful and are still super shady.