I don't have symmetrical defined corners.
AN speakers do not necessarily have to be placed in the corners. I know several folks who use their ANs (and Snells) in the middle of a long wall. You will have to play with toe in, and the placment from the back wall might need to be tweaked for each speaker to even out the sound at your listening position.
It sound like you have a less than optimal room. Welcome t the club. There are no perfect solutions (other than building yourself a more perfect room). I think that you are either going t have to accept some compramise in sound or speaker placement. Or you can try to correct for the the room acoustics digitally via a Tact or some other room correction device. That's not my cup of tea, but it's an option.