Moms Panelist Brigitta tells me that I gave some wrong information about this question previously. (Thanks Bri!)
This is what Brigitta says: "There is a character dance during the Extra Magic Hours at Hollywood Studios. My daughter and I have participated in this many times and she loved it. There is Mickey and Minnie and I have seen JoJo and many other characters there as well. They dance with the adults and children inside Disney's Playhouse during the Extra Magic Hours to a DJ who plays all kinds of music and there is even a guy who makes all kinds of free balloon hats and animals for the kids!"
If you're interested in the Playhouse Disney show, you may also be interested in the
Playhouse Disney Play 'n Dine character breakfast and lunch at the Hollywood & Vine restaurant, also at DHS. This meal features Playhouse Disney character favorites from JoJo's Circus and Little Einsteins. This perhaps the most interactive character meal at WDW. The characters (and some human hosts) lead guests in songs and dances featured on Playhouse Disney. This is a great spot for any energetic Playhouse Disney fan. To make reservations for this, or any, character meal, call Disney Dining at 407-WDW-DINE.
I'll be more careful about triple checking my answers next time. Sorry about that. Thanks again to Brigitta, and hope you have a great trip!