Let's take a look at some of the color symbolism in The Mentalist regarding RJ.

RJ's main color is obviously red with the smiley faces but his secondary color is yellow - remember the yellow flowers left with the naked corpse and at Dr. Morning's office where Hicks was found dead in His Right Red Hand.  If RJ has another color, it's orange.  Tigers are orange and RJ is the tiger in William Blake's poem.

Recall that RJ has been known as Roy.  It could be that he chose that name as a stand in for the colors Red, Orange, Yellow - ROY.  If RJ claims the first three colors of the visible spectrum, that leaves Jane with GBIV - green, blue, indigo, and violet.  I would say that Jane is blue and Lisbon might be green.  I won't even try to guess what colors the rest of the team is.

Color is definitely important.  Take Lorelei for example: when we first met her, she was wearing bright red but the last we saw of her in Red Sails in the Sunset, she was wearing a nice yellow dress.  Lorelei is moving closer to Jane's colors in the visible light spectum as he lures her away from RJ.  It would be interesting if she ended up wearing green/blue when she finally chooses to help Jane.

And as far as the suspects go,  Mashburn is the only one that is constantly surrounded by the colors yellow and red.