1. For HT don't set the M80's to large because you are duplicating the LFE channel when using Dolby digital tracks as well as introducing phase and other artifacts when in stereo mode. I would suggest turning off the EP500 and just listening to the M80s full range for music if the Denon has such a setting.
I think you misstated this. The Denon LFE+Mains setting does not duplicate the LFE channel. It only copies the signal below the crossover setting that is being sent to any speakers set to large and also sends it to the subwoofer. The LFE channel plays only through the sub as long as the subwoofer is set to “yes.”
First off I don’t dispute the phase and other issues you mentioned or the benefit of not burdening speakers with playing very low frequencies since that’s what the sub specializes in.
But this brings up a question I‘ve been wondering about for some time. If duplicating low frequencies between the “large” speakers and the subwoofer can cause so many problems why do so many people recommend using multiple subwoofers to even out the bass? Won’t the same issues apply or does evening out the bass outweigh the other issues most of the time?
