Color is often used intentionally in movies. I found it interesting that in Frozen the color palette for the winter dress that Anna bought in Oaken's store is similar to Elsa's coronation dress. I don't know why the producers of the movie decided to depart from what seems like Anna's standard green palette.
This is discussed in the "Art of Frozen" book.
[Michael] Giaimo is an extremely analytical designer, and when he imagined the costumes for the characters, he applied rigorous aesthetic standards. "For Anna's travel outfit, I wanted something that would be really striking and bold, yet elegant," he begins. "She's a princess, and that really blue skirt says royalty, as does the magenta cape. I thought those two colors would be really striking, because there's a rich saturation to both of them. But there's always a little bit of black on the characters: it helps anchor the saturation, so it doesn't float into the atmosphere."
The warmer green palette was reserved for Anna as she grew and reflected her "sunny disposition". Obviously by the point in the film that she's changed clothes, her disposition is slightly more reserved.
To reflect her sunny nature, Anna's color palette during her growing years is kept on the warm side. Grayed yellow greens, ochre, and olive dominate.
I think they are equals, they both lead in different ways. Elsa even said the line about the bridge having two sides/daughters at the end! Some people relate to Elsa (like me), and some relate to Anna. It's a perfect balance and the last good thing in my opinion, Disney did, though Jennifer Lee is who is to thank and the people who worked on the film and designs, not Disney.