Thanks for posting the info. They do take a bit longer to find, but now that I know what to do the mules are moving at a steady pace....
What a fun, yet exhausting and expensive day this has been!!!
After you enter the Lobby of the Haunted Mansion, walk over to the left and enter the crypt. (this used to take you to the monorail station) There are three rooms inside and each has a ghost which will appear at some point. Click on the ghost in each room for credits.
If you just stand around waiting for the ghost to appear they are less likely to appear- I did notice that today they were staying put a lot longer but the one in the ball room especially tends to stay invisible more than visible
I did notice when running mules through that often if I made my character go around in circles that he would even come and dance with me lol