if staying with a friend do you need the proof of their address. they are a foreigner in China. So would they need to scan the contract?

If you want to stay with your friend, you are highly suggested to provide the copy of the contract for your application.

For your situation, you are suggested to plan your itinerary as soon as possible and then booking the flights tickets and the hotel for your traveling according to your itinerary. Then provide an invitation letter from your friend, hotel booking confirmation, flights tickets and the copy of the contract to the embassy to make sure you get the visa smoothly in the end.