Hi! I'm here with the review you requested a little while ago. :)
First of all, I'd like to express my awe of you for tackling this concept of five very different girls living in the same house. It looks like they're going to alternate chapters throughout, and that's definitely a lot of things to keep track of! It's really cool that your idea is going to grow into something very, very big. :)
About the tense changes: At first, I didn't notice them, but upon further inspection, I did. I think that most people might not notice it, but just for consistency's sake, you might want to pick a tense and edit the chapter accordingly. It makes for a more connected chapter overall, I think. :)
About Etty: She's mean, 'tis true, but maybe there's something else there? She, as a twelve-year-old girl (she IS twelve, right?), is bound to be catty and mean sometimes--I still remember middle school, and the raging hormones make that sort of thing hard to avoid. It's great that she's so passionate about music and fashion designing, because that gives her a creative outlet for all that added Veela drama. The thing that I'd really like to see from her character in the future is a more rounded-out personality. I totally understand that right now, it's only the beginning. She's got a whole road ahead of her, but along that road, I'd like to see some surprises. Maybe she doesn't fit in at Hogwarts, or maybe someone is mean to her instead of the other way around. Something needs to happen to her to help her see that the world is not hers to create and destroy at will. With a little introspection, Etty could become a great person. She just needs to spend a little time in other people's shoes. :)
One point of confusion: I read your first chapter, but there were things mentioned in this chapter that I was confused about. How old are all of the girls? How old is Donaugh? It's just a little unclear to me, and I'd like to be sure of it.
As for everything else, your spelling seems to be pretty good, and your grammar is good, too. There are a few sentences that could be tweaked, but otherwise, you're golden. :)
I also like how you've got little factoids about the characters. It makes things a little more personal. I think it would be really cool if you could weave those into the action of the story after you mention them. (As in, you mention a fact in one chapter, then a couple chapters later, you weave it in.)
That's all for now! :)