well, still to this day it is all legend and tales.
There is an excellent treatise on Buddhism in China though by Kenneth Chen.
http://www.amazon.com/Buddhism-China...6890013&sr=1-1
These kinds of scholarly works are much more valuable in understanding the history along with the oral histories as handed down in martial arts schools or among sectarian schools of buddhism in my opinion.
If you sort through it, you can find answers...sort of.