You can find Mary in the gift shop, I believe it was in United Kingdom at Epcot. She was up front and Winnie the Pooh and Eyeore were in the back signing autographs. They don't really announce it. We found alot of characters in Epcot, in the Nations, lurking around the corners. Like I said, they really didn't announce them.
Mary Poppins, Winnie the Pooh - United Kingdom - inside one of the giftshops
Belle & the Beast - France - out back
Jasmine & the Genie - Morrocco
All kinds of characters - on the left side of the gift shop on the left side
of Showcase Plaza - Port of Entry or Disney Traders?