Your speaker placement looks ok. BUT first off the center speaker needs to be centered under the tv and between the L&R speakers (now it looks as if its offset to the right). Second I would pull the front L&R speakers away from the wall a lil and place them a lil wider and toe them in. As for sub placement one drawing you show one sub and the other drawing you show 2 subs. I would highly recommend 2 identical subs if you only have one. Corner placement will yeild the most spl, BUT with an open floor plan you may want near field placement so you get the feel and sound without having to pressurize the whole area. So I would try one sub on each side of the couch between the couch and the recliners. That should give all listeners good bass response.