judging by your jpg I think you need to plan on having your side surrounds at least even with the seating area if not a little behind it. HAving them in front is not really ideal.
Would it not be possible to put the couch up even with side surrounds? or perhaps if you plan on pulling it up even with the surrounds during movies that would work.
Also it looks like you are planning on placing the ep500 in front of the left m80... I would not reccomend this. If you had planned on raising the m80's above the ep500 I think that the tweeters will be too high.
anyway, you do have a challenging room- with a little planning and experimenting I am sure you will find the optimum set up for your given room
