I haven't been keeping up with Once Upon A Time, but I'll make an effort to watch Amy Manson as Merida from Disney Pixar’s Brave. . Odd, that red hair of Merida's reminds me of someone I know.
Manson played Alice Guppy in Torchwood, Abby Evans in Casualty, Lizzie Siddal in Desperate Romantics, Daisy Hannigan-Spiteri in Being Human and Medea in Atlantis. You may also remember her from Not Another Happy Ending (2013), Pumpkinhead: Blood Feud (2007) and Bloodmonkey (2007).