JTF,
China insists that employees are "family", while a part is just nice words, they really believe a part of it.
My feeling is that if possible they will honestly try, not to fired someone except for safety reasons (read for not following the books!).
So in my opinion, it is quite possible to make a long carreer in China, if you can accept their company culture wich is certainly easier speaking mandarin. Some pilots (expatriate) have been here quite some time.
Now, I may be completly wrong and if faced with a choice between a local and an expat, their choice will be obvious.
I am afraid that nobody can answer your question not even CAL management, because it will be different guys in ten or fifteen years and rules WILL changed.
Nobody can predict future for the next 25 years....