The first photo of Natalia Tena in Tonks' costume (purple hair) has surfaced online! You can see the photo
here.
I love the clothes but want the hair to be shorter/spiker. Perhaps it will be for the pink look? I will be most disappointed if we don't get pink and spiky at some point in the movie but I would have been equally disappointed if her hair had been pink and spiky the entire time without changing.