At present, I have to say it is extremely unlikely foreign FOs could be hired by China's SOAs (state-owned airlines). Do you know how much paperwork it is involved that the airlines and government authorities have to deal with? (Not to mention the expat FOs). The time wasted just on paperwork is definitely not worth it for the SOAs to do this.
As for private airlines, well, you have to understand that they have much more difficulties in getting enough pilots, that's why some of them have or had expat FOs. In China, most flight training institutes (I am not saying all of them) have partnerships or some sort of agreements with Chinese SOAs, so most graduates will end up working for SOAs, and this is only one of the many factors why SOAs are not so short of Chinese FOs, hence almost no need for expat FOs.
Cheers.