The requirement for Air China now is for 25 Captains. It is part of the deal with Airbus, who I am not 100% sure but I think will supply the pilots or at least pay them. It is for the new aircraft they are getting delivered now. They do not have any foreign FO's there. This information is from a person I meet from Air China recruitment, that I met while doing CAAC exams for another Chinese Airline, so I would take it as accurate.
Do not get Air China mixed up with China Airlines who have been hiring foreign pilots for a long time, but are based in Taiwan. Air China has only recently started hiring expats.
Most other Chinese Airlines that hire expats are also only hiring Captains at the moment, but there are some FO positions if you search hard enough.