The biggest concern I have is that the seating position is in the center of the room. This is usually an audio null area and is probably the least desirable seating position.
If the L shaped counter can be moved or deleted, it would allow for a more recommended 2/3 back seating position.
The right wall will definately need acoustic treatment but the asymetrical layout may actually help overall acoustics.
I would suggest placing the rear surround speakers higher up and even with the listening position. I would hang them from the ceiling. Their placement is more crucial to the sides than their final height placement (final placement is also determined by speaker design).
Sub placement will be the most critical and placing it catycorner to the prime listening position would be a good starting point for testing. I would not be too concerned with furniture placement until this testing was completed. Then, you can work the furniture as best you can around the subwoofer placement as it will have an equal, if not greater effect than the center channel placement.
I always recommend audio testing before placing furniture. You may have to make some compromises but at least you have a starting point that is optimal. Trying to design an audio system around a predetermined furniture layout is a step backwards and is rarely a recoverable design.
Here is a link that to Harman International. Some good white papers to mull over before commiting to prewiring and furniture selection.
Whitepapers
