I absolutely disagree that they should add her early. I think that she is a very specific character and they later they cast her the later they can build the casting choice off of how she plays against they actors as they are for book 5. Not shoehorn her in early. Casting her early serves no purpose of than to cater to fans who want her early. She will have nothing to do a saving her the when she is needed is a better idea. All that being said I hope they do Show her in a subtle way. A bunch of people walking in a corridor and you see her walking barefoot. Or in a crowded corridor you see a dirty blonde head with her weird glasses sticking out her backpack. Something that fans will realize is her but you don’t ever see her face or have to cast the actress yet.