Name significations :

Bret Stiles : Stiles = to Steep ascent  Bret comes froms celtic language , bre means something higher than you , T represent the bridge or the passage between heaven and earth . To become god

Gale Bertram : Bertram means bright raven which represent the perfect occult Messenger and secret keeper . So he receives orders from Stiles and calls the shots.
                        Gale means : Happy God; Father in rejoicing ( satan and stiles are happy )

Brett Partridges : the second T here shows us that he is connected to stiles , partridges represent Satan who wishes to steal all souls from God just as the partridge steals eggs from other nests. Wiliam Blake painting shows 2 birds , so 2 killers. His main task here is of course to clean the scene but also the ritual aspect.

 
Reede Smith : Reede is related to the color red ,blood
                        Smith means he works with metals , forging Swords , knifes.
Also : Roy is related to the color red , ruddy , blood
          tagliaferro : ironworker or a nickname for a strong or ferocious fighter

Ray Haffner : Raymond means a protecting hand
                      Haffner  means a potter , Pottery is made by forming a clay body 
God blessing ?

Thomas McAllister : Thomas means twin , mcallister comes from alexander which mean protector of men , he wants to be a good cop.

Red john : John means Yahweh was gracious ( for the souls) , the red here is linked to the red devil,sins desires of sex, money and fame . So Red John is satan's will done by a cult.
Stiles is the face , the killers the eyes , the Messenger of the occult secrets the mouth.

Patrick Jane : Patrick means noble man  and janes means Jehovah has been gracious. I think thats why he doesnt kill or let Jane die , because in death he cant have him.

sorry for my English , if sometimes its not clear just get the whole idea and look into it im sure u will have better words than mine to explain.