O.k. This might be bogus, but you tell me since I won't be able to try it for a while considering my position in the game. I heard that there are hidden gallery ghost that appear after a certain condition is met. After you beat Vince Van Gore and before you fight king boo. You go to Bogmires grave(2nd boss). With the fire equipment you light the tombstone on fire and two new ghost apear. One is called Dash and can be found on the roof. The other I forgot the name but can be foud on the balcone. Asuming your closing than me trie it out and get back to me on it. I'll try myself but I want to hear what you think.