OK I am probably one of the posters that knows the most about this subject as I know one of them, met the others during the USO (they gave me free tickets).
The Chinese National Team (Na Li, Tian Tian Sun, Jie Zheng, Yan Zi and Ting Li) travel with a number of coaches. There is one who is the head coach for the national team and then there are two others (one for Tian Tian Sun / Ting Li) and one for (Jie Zheng / Yan Zi). These pairings make sense since those are doubles teams. Na Li doesn't have a coach that is dedicated to her.
So far this year (the first real year on the tour) all 5 girls have been traveling together from tournament to tournament. There are very few instances where they will split up due to their rankings. At a higher tier tournament like Dubai, Na / Jie will probably be in qualifying while the rest will play doubles only. At a lower tier, Na / Jie will be in Main Draw while the rest will play qualifying and doubles.
I am not sure if these coaches are the best in the world because they have never competed themselves at a world class level. The next generation of Chinese players will people like Na Li as coaches who have played at the world class level before. So this makes a big difference. Of course there can be a coach like Richard Williams but not very likely.
Shuai Peng has lived in the US since she was a teen and trained with a Chinese male coach in Florida (also trains Janet Lee and Nan Nan Liu).