I don't know if the exact dates for the Osbourne Lights are out yet, if they are I am sure someone else will chime in.

Last year they opened on November 8th.
As far as Fantasmic! I don't beleive you can book that far out yet. When you can, you can book on line at WDW under Dining Events. It must be prepaid at the time of booking.
Have a Wonderful Trip!