I'd correct some things:
Why would she do such a thing?
("Why did that happen?" doesn't sound very natural although it's pretty much literally what it says)
Haha yeah I haven't gone through the scripts yet to make everything sound more human. I'll do that once I get a better idea on how they talk and the little ways in which I can build their character.
Good to know that White cloak talks a bit stiff. I'll consider that for a few other parts of the translation I have him talking in so far. I had read that he refers to Draco as おんなのこに which is more used in a derogatory meaning when males use it to females in conversation. So thought chick kind-of suited.
(this part was pretty good but I had to add in him saying that he hasn't seen it either (わたしもみたこともない))
By using わたしも
) isn't this him saying "as part of his joke" that he hasn't seen it either
I think for the joke purpose of this, I'll try to go with something like
"Yeah, it's NEVER been seen. I didn't have it because I've never seen it either. Ahahahaha."
"Yeah, nobody has SEEN it before, including me. So I didn't have it. Ahahahaha."
Thanks for all your help on this.