You cant switch between 6 and Edge since the Edge have a longer cable going from beneath the mainboard. And Yeah great guide.
Ive successfully removed the subwoofer and just added another old speaker to the system. In this way the old speaker plays the base and the sonos plays the trebble. It actually works quite well. It doesnt look good but its a way to fixit if you can find a good location for it. I got my sonos play 1 from a friend who dropped it on the ground so for me its just a free speaker.