Hiya Patricia!
I love it! I so so so hope that I see you in full costume there!
The Haunted Mansion has bunches of fan sites and blogs out there with amazing pictures. I came across so many that I've been lost in pictures for almost an hour now!
Instead of even trying to list all of those sites, I'm going to tell you the Google phrases I used. Google the terms 'Doombuggies', 'Gracey Disney Haunted Mansion Dancers' (that brought up some super cool sites), 'Long forgotten Haunted Mansion Disney', and in Google Images put 'Dancing Ghosts Haunted Mansion' for some good images.
If you go to the Flikr website and search 'Dancing Ghosts Disney' a bunch of great parade pictures come up. Good views of the makeup and costumes.
I hope some of that helps with your inspiration...I know I've been inspired! Thank you so much for the super fun question!