I am using my Ravenclaw icon because this issue has to do with Houses, not necessarily for Myrtle (whom I don't really claim any affinity with). I don't really care about ghosts.
Tonks, on the other hand... all I can say is WHAT. Or maybe I should say WOT. Because, honestly, JKR, what the hell? Does anyone get the feeling that she wanted someone "cool" in that house and so she shoehorned in someone that was available? If anyone has seen the case being made for Tonks to be in the house she turned out to be in, I would love a link to that write-up, because right now I'm ... dumbfounded.