The parade is cute! My DS (5) loves it. They just added Lighting McQueen and Mater from CARS. Its all characters, and most of them are in cars that drive past. A must see? Id have to say no.
Things I would do with a 10 year old and a DV ... Rock n Roller coaster, Tower of Terror, Stunt Show, Indiana Jones, Great Movie Ride, Maybe Star Tours and Muppets if you had time. YOu probably wont have time for the parade if you have to be at Cirque at 6, and need to leave MGM, get back to POP, get ready and get to DTD. You can see tons of characters out and about at MGM.. near the hat, on Mickey Ave, Buzz is at Al's toy barn, Chicken Little is there I think ( although we didnt see him) You can now see Mater and Lighting McQueen back on New York Street.
The problem with trying to get alot done at MGM is that most things are on a time schedule. Pick up a park times schedule at the front dest and try to preplan what you would like to see and at what time. For instance, when we were there, the stunt show was at like 11, 2, 5. That was it. Id pick the top 5 things you want to do, and get those done and see where you are time wise. Have fun!