Just a guess but I believe the one facing away is a young kumagawa misogi. The bottom right has the member of the 13 party who is always wearing a mask whose name is yukuhashi mizou and the one right above that is munakata kei the hidden weapon user. At least I think thats who they are. I know the one in the background is from the plus six portion of the 13 party but I don't know the name.