Someone pointed out elsewhere on this forum, too, that their wives are similar: Alma wears pale, neutral tones (in an interview, one of the costumers said they looked for clothing for Alma that suggested sadness, reticence, someone who stays out of others' ways), while Lureen always wears red. She's got that red hat on when she first meets Jack, and she wears red lipstick and all those ugly rings when she has the phone call with Ennis.
I always think of Ennis and Jack's colors in association with times of day, too--Ennis wears pale colors and looks up the mountain at Jack during the day, while Jack wears blue and black and looks down on Ennis's campfire from the mountain at night.