According to Broadway.com:
"To celebrate the tenth anniversary of the ever-popular Chicago revival, there will be a starry benefit performance of the musical on November 14 at the Ambassador Theater. The show will be done in its entirety, with different stars each taking a number. Original principals Ann Reinking, Bebe Neuwirth, James Naughton, Joel Grey and Marcia Lewis will all participate in the event."
So the original revival cast won't perform the show in it's entirety. They are having tons of different alumni come back, each doing a number.
Tonya Pinkins: Then we had a "Lot's Wife" last June that was my personal favorite. I'm still trying to get them to let me sing it at some performance where we get to sing an excerpt that's gone.
Tony Kushner: You can sing it at my funeral.