You won't be able to see illuminations and unfortunately, unless you can go another night, you will probably have to choose between Le Cellier or Illuminations.
I'm sure Le Cellier is booked up by now for the night you have your ADR for so I'm not sure you can move it to an earlier time unless you keep calling everyday and see if there is a cancellation.
Another option is to get the candelight processional package when it gets released and try to get a table at Le Cellier earlier and that way you may still be able to watch illuminations.