My friend said she did not see any pick-pockets in Jiuzhaigou when she was there.
The toliet did have doors, but most of them are dirty.

In Jiuzhaigou and Huanglong you don't have to worry about pick pockets. In train and bus stations in Chengdu you should be careful.

Many public toilets in China do not have doors or sometimes don't have dividing walls. They can be dirty as well. Airports will be better and will have doors but still can smell quite bad. Jiuzhaigou and Huanglong toilets are quite clean and do have doors.