i like the mid one, the oranges palette works really nice with the pale violets, the green variants are too much aggressive imho, personally i would try to implement the bkg to add a lighting element, if the cauldron is your main light you have to figure out better the shadows it will cast, but if its your secondary (if it is like a fire or a lamp the decay of the rays can make it more like a glow) you can have maybe a direct ray to shape your character the way you feel better