Red John has to be charming and somewhat good looking as he seemed to have quite a way with women.  This lets out most of the suspects.  Bret Stiles, although he has the charm, power and money to pull off all these murders is too old to fit the profile.  Kirkland is too creepy and doesn't seem like he has money.  Haffner is reasonably attractive, can definitely be charming and has enough money to at least own his own business.  RJ also has to be in good physical condition.  Bertram is slightly too old and does not seem in good condition.  I believe RJ is Haffner, his accomplice is Kirkland and maybe they have Stiles with his money backing them.