I visited thursdays party and didn't even see them. However, I read over on disboards.com that they are just there as part of the dance party area, but I have seen photos of guests with them in their trip report
On Friday 10/17 they were in the the Pirate's Wharf dance area, dancing with everyone - so you could take pics there. I don't know if they'd pause to "meet and greet" and do autographs, though. They seemed to be in high party mode!
Last year they were set up for meet and greets where Jack Sparrow and Peter Pan are this year in the wharf. I didn't see them when I went Friday though, but I didn't go over by the dance floor. Donald was out for meet and greets last year too and I only saw him in his farm/rodeo? outfit in candy corn acres.