It seems that you are also publishing this elsewhere, so just link it to respond to God.
As one person mentions there: "Air China in Beijing does not care. I have seen that the staff hired at Air China stations is more demanding, but if you leave Beijing you will be fine.
I have traveled with two hand items in Air China. They certainly allow a jacket and a bag. However, the obvious solution with a coat / jacket is to use it on board.
I have also flown with a suit bag in many airlines, and I have taken it on board in addition to hand luggage. (Now I have a Skyroll suit bag that I can check instead). What I used to do is walk to the customer service manager while boarding and say "Did they tell me you would have a place to store this for me? Or can I put it on top of my seat?" It is the answer of the two options: it was not & # 39; no, it is not allowed & # 39 ;, and most of the time they have offered to keep it in a closet for me!
You are unlikely to receive criticism if you are courteous and sincere. Ask how they can solve the problem together.
It is also worth checking again when you register: "Can you keep this on board for me? Or can I put it on my seat?" He will give another answer later: "Registered in person said he could bring it on board!"
Again, don't be an idiot about it, but the crew is also people and understands that the rules don't fit every situation, and they don't want angry people on board with them either. Usually they will try to help.
Another alternative is to take a digital copy and print it in China? I am sure that your hotel or conference can direct you to a place to print it. Of course, this means that you have some time to do this in Beijing.