Spoke too soon. Connie’s CV is added this time (in the chimi specials; in this picture, Connie is to the left of Jean). Now there’s no way to guess who’ll be on vol.7 cover; but it will probably be revealed in the next few days. (I am also counter-jinxing by saying, “Marco won’t be voiced in the next chimi special” )
And..yes, quick preview of screencaps (from the volume 6 discs set) can be found on that wonderful blog page.
EDIT: and here it is. volume 7 cover Erwin and Hange, and Hange gets the inside cover. Jean made it onto the included calendar as well (for some reason) – Jean, Armin, Mikasa, Eren, Levi and Erwin, in that order from left to right.