Hi Nick, welcome.
I don't think you have anything to worry about. The QS series speakers are really quite forgiving relative to placement. I would very strongly suggest that you use either the QS4 or QS8's and figure out a mounting method that works in your room. They are terrific speakers.
Some people (sirquack, in particular) have had wonderful success ceiling-mounting the QS8's. Likewise, the Axiom Full Metal Bracket can give you some more options if that skinny wall won't accommodate the full width of the speaker.
My only concern is how very close the second row is to the back wall. My experience under similar circumstances was fine relative to the surround effects, but left quite a bit to be desired relative to the main soundstage (reflections from the back wall muddied the image quite a bit). Likewise, you should probably try to ensure that your mains are a bit closer to the middle of the room (rather than the side walls). My understanding is that early side reflections compromise sonic imaging quite a bit. You may want to consider moving the entire seating arrangement a bit closer to the screen, and/or considering the application of some sound-absorbing treatments on the side walls betweent the mains and the primary listening position.
Good luck! We like pictures!
