I don't think you need a 7.1 system there buddy...
seriously I think you might have enough to deal with trying to hang some adp's on the walls around that window.(possibly build a bracket to hang them in the middle/top of the window)
In that room config.. I would lean toward the adp's as long as you can find a place for them, and I would also suggest you pull the furniture off that wall... at least a few feet.. if possible.
IMO - - You do not want ADP's for the rear wall (they serve a better purpose on the sides)
Rear surrounds could be really small like
ORB audio's... and have served many very well.. If I was going to add in rear surrounds I would go with Orb's, small unobtrusive, and cool looking.. they really just add in filler sound (more immersion), and are basic copies of surround left and rights..
But with that small of a room, the ADP's will be bouncin off the rear wall behind you to give you that filler... that is what ADP's are meant to do...
Don't spend big $$ on a 7.1, start with the basics, and add more later, If you really think you need it. Trust me it will sound awesome !!!
You've done your homework, and have picked out some great stuff there..
