Nice analysis of colours.
Rudra - Yellow is so mellow and so soothing, and brightenes the gloom. That is our Rudy. The peacemaker. The guy who belives in maintaining the equibilarium. Yellow can also be bright like the sun. The sun is hot and angry. Rudra Avatar of Rudy we see rarely. (Love angel reveal, when he blodied Riyaan when he was jealous). Rudra is real. The most "Real" out of the brothers.
Omkara - The white. White is the colour of purity and light. Om lives in a dark space, but the only whiteness in his life is his "Belief" in the truth. He beleives in it totally. I understand his ideology, because my favorite line from the Bible is "You shall know the truth and the truth shall set you free!" Does that mean I never lie or have never lied? No that is not what it means. It means I "Believe" in the truth. I think Truth is supreme. Even when I cant say it, I still beleive it to be supreme. That is what Omkara is like.
Shivaay - Blue like the sky, blue like the Ocean. He is everywhere. The great wall. His love for his family sky high and as deep as the ocean at the same time. When I think of Shivaay in the context of his family I am reminded of this lyric. "Tu Jaha main waha...sang sang yu chalu tere...jaise tera asamaan". That is Shivaay.