Well ghost types are strange, unexpected and not always what they seem, right? Plus so far in gen 5 allot of the psychic types have had bows. And since eevee already has a psychic and dark type ghost is the next closest thing.
Oh, um... Okay. Well... I think IT'S either flying or a brand new type and I think it's an IT because I believe that it having two different genders for the same type defeats the point of an eeveelution.