I can't really see her as an Errowyn because PD's blue roan filly is named that. I don't know why, but my first thought was Folara for her. I can certainly see the TBxBelgian. I see the draft in her head/neck and coloring and the TB in her legs and body.
Surprisingly, there are very few synonyms for Frost
. Maybe Chill or Knik (name of a glacier in Alaska).