That's the cover for #10 variant cover, by Georges Jeanty. The woman in the middle is "Robin", the winner of Joss' contest. This 'very special issue' will feature her, as well as a heart to heart between Buffy and Willow. The interior is drawn by Cliff Richards.
About #11, the other standalone. Looks like Jeanty will be drawing that one, from the piece of press Dark Horse just released.