I can't really answer your specific question about the adults only tour, but there are no DISNEY characters on this tour. You will not see makeup or masks on anyone (which was good for my daughter, because she is scared of characters, even the Disney ones), just costumes/wigs. The "characters" that are present at various locations are not "kid-y" and are more for your education and entertainment, than an incarnation of a cartoon. I would think most of them would still be there, and that you'll enjoy them.
There are a couple that might be more geared towards children, but I always found that they were so wrapped up in the history of the place and the inspiration of the Grimm brothers that it wasn't offensive, even to the teenaged boys we had on our trip!