Sorry, I don’t have the answers to your question. I’m just a fan, not a representative of Disney.
They did change a lot of the original story of the Snow Queen and made it their own thing for Frozen, but Disney always does that with the majority of their fairy-tale based stories.
I know Glen Keane made a few concept sketches for Frozen, but I don’t think he was very involved with that particular project. (I could be wrong though!)