Red John, although having a sophisticated cult like following, IS 1 single individual male and not a number of people posing as te same individual. We know this due to a) the discription of the blind woman as to him being a male of average height , loving classical piano music, soft but rough hands , etc. b) his voice we hear over the radio strapped to Waynright, c) always referred to as he or him and d) this last episode "red barn" proves that he was in fact a member of visualize who worked on the farm.
The last episode also proved that Red John was or still is a member of Visualize . Which would help explain why Bret Stiles told Jane he had privlaged information on Red John & would also explain part of Red John's having a large organization & resources like Visualize.
We also know that Visualize has the 1 mole inside te CBI as revealed in Red Barn, but also Van Pelt who seemed to open up to Stiles while in custody, had the outburst while questioning the priest, where she defends Visualize, is obviously a suspected mole now as well.
Bret Stiles may not be Red John, BUT there is no doubt in my mind that Stiles knows who Red John is & still has communications with him.