No information about the role Cilan, Chili, Cress, Lenora, or Iris will play in these games, or if they will even appear at all. Brycen will appear in Pokéwood.
The guidebook itself is set for a June 30 release, and will retail for ¥680.
Update: An image from the inside of the guidebook shows a modified type-effectiveness chart in B2W2. According to the chart provided by the guidebook, Ghost-type Pokémon are no longer resistant to Bug-type moves. Note that this could simply be an error in the guidebook itself.