Hi Jacqueline,
The only other place at Walt Disney World that I am aware of where trick-or-treating has been offered on 31 October in the past is Downtown Disney.
Details of the 2010 Happy Haunting event were posted on the Disney Parks Blog on 22 October 2010 which you can see
HERE
Kids were able to dress up in costumes and go trick-or-treating throughout Downtown Disney. There were at least 20 shops and restaurants throughout the West Side, Pleasure Island and the Marketplace that offered goodies from 5-9 p.m. There was also a kid’s DJ dance party at the Waterside Stage, a magician, stilt walkers, storytelling and a few other happy haunts.
I would expect something similar to this will take place again this year and would recommend that you subscribe to the Disney Parks Blog to ensure that you receive information about what will actually be offered once it is available.
Wishing you a spooktacular trip