Hi there, Amanda!
The Fantasyland preview, starting November 19, will allow Guests to visit the expanded area prior to its official Grand Opening.
This "soft opening" will allow Disney Cast Members the chance to check out crowd flow, ride queue times, and other logistical issues that require "real people" for testing.
At this time, there has been no formal release of what will be operational in this part of the expansion. While it is assumed that everything slated to be open will be functioning, this soft opening does allow for that important buffer prior to the grand opening.
Keep your eyes on the
Disney Parks Blog for any and all updates regarding the preview; that's your best source for breaking information.
See you later, celebrator,
-Deborah B.