I like it a lot. It is trendy, but it's been trendy for quite some years now, which makes it less trendy than say, Jayden or Nevaeh. I'd just spell it Hailey but the other spellings you listed are fine. Vanessa Hailey is neat, Vanessa is kind of an exotic, classy name and Hailey more ordinary, which balances the combo out nicely.