Basically everyone who appeared in Lisbon's dream (assuming people are up-to-date)
are relative to the core plot within the Red John story arc, at this stage it's pretty clear those men are all a part of the so called 'network' of Red John's people.
The show has sited Jung and reveals truth in dreams. 
This dream however deliberately avoids including Brent Stiles.
Clearly the man is one of the only ones capable of influencing peoples minds n hearts, 
to flip the logic on it's head and make the cult like Red John image work.
He is a tremendous actor therefore worthy of the role of Red John. 
He was very clever in getting into Van Plet's head very quickly, he's rich powerful and really the only one who could match Jane. The others are minions and have taken on important roles in the whole operation. Jane cashed in an important favor from him at one time also that lead to the assumption that despite his virtue as a cult leader he remains in touch with the underground parts. 
He will be able to give the script a good read play the part well, vex minds and be hidden the longest. If anything, I would see this as a safe and logical step in the already 6 season arc, I mean come on!