The Ending (spoilers, of course)

So I'm having trouble understanding the ending. After Francoise escapes, sees the old woman with the funeral carriage and decides to choose immortality and servitude after all, she returns to find Morgana, who shows up and takes her back. Morgana then leads Francoise back to the barn where Francoise and Anna fell asleep together, which set the adventure in motion in the first place. Francoise looks through the window and sees herself and Anna, still asleep together in that barn, and smiles.

Was this a variation on the common "It was all just a dream" ending (read: Anna and Francoise never left the barn, and that's their real bodies in there, still asleep and eventually to awaken and end the dream)? Are the Anna and Francoise in the barn mere changelings or doppelgangers, created by Morgana and left there to carry on with Anna and Francoise's lives in the real world (with the real Anna and Francoise secreted away in Morgana's castle)? Or is the ending meant to be something else entirely?