Misty is the best out of those for the sole reason that it's the easiest for the dog to learn. When naming a puppy, you should go for a name that's short, distinguishable and not also the name of two billion other puppies. It can be a bit confusing for the dog if she hears her name yelled all over the place.
Misty is good because it has two distinguishable syllables. Other names that would be good when thinking like this could be, for example, Yuki, Sara, Luna (isn't she a character in HP, too?), Ginny, Audrey, and so on. Go for a short, easy name like that. Make it easy for the dog, don't just think about yourself ^-^