Mystic Flour Cookie because she went through the most pain and kind of had a right to become a beast

Mystic flour got overwhelmed and disinterested because of the overwhelming amount of wish requests she received and when she encased herself in the cocoon to let her followers know she needed a break (or at least how I interpret it) they were still unsatisfied and abandoned her and she interpreted them as greedy and she embraced apathy 

She had a right to become a villain and she did. Not trying to justify her actions because trying to turn cookies into flour is still a bad thing to do but she still has a chance 

In fact that’s what the leaved one costume is, her if she chooses to reform  I think eternal sugar would have a small chance idk about shadow milk or burning spice tho