Of characters who have appeared so far, my favorites have to be the Piggy, Goldilocks, and Pinnochio. I squeal when I read the scene with those two together, they would be an adorable couple, and you can tell Pinnochio is in love with her and that Goldi kinda likes him too but isn't considerring it in any serious way, prolly because her evaluation is so soon and she may have to leave him there after. Also, I love Goldi's optimism and compassion.
Of characters we haven't seen yet, my favorites I think are Rosie&Posie (I consider them a single entity) and Master of the Stalk (Janck the Giant Killer, totally). Jack seems so sinister and just has this kind of aura of power and arrogance about him. I loved the one pic of Rosie & Posie in Endling's DA gallery that had the text of their file in the background, I wish most of it hadn't been covered up and that we could read profiles like that on all the patients in Everafter (at least, the ones who are main characters).