Sorry for double post, just to post the poorly designed ground floor built in 5 minutes with laptop touch mouse by GIMP. Just to give a basic idea of the outline of the mansion.
[img]http://i.imagehost.org/0161/test.jpg[/img]
Servant's quarters are for when this mansion used to be inhabited. Now there are no servants there, so it's basically an empty place. What is IMPORTANT there is that there are 4 MASTER KEYS in the Servant's Room, which can open any door in the mansion. And for backup, there's also a key store, where there are 2 of each key to a room in each mansion, in the Servant's quarters, opened by the Master Key. Each person will take one key, unless they request to have both. You people will have to discuss in the RP how you would like to distribute the Master Keys.
Hope this gives an idea. And I don't think we can start the RP without about 10 characters, or else the Murderer kills 2 people in one go now and the Challenger can't solve it and it's all over.