a = yes
b = yes
c = yes...maybe. The sonus has a total powerr output of 2x55W into 8 ohms so there would probably be enough volume for some background music with all pairs on, but don't expect to be able to support a party in each room.
When you wire speakers in paralel, which is what the QED does, you decrease the resistance with each pair you switch in. So, if all your speakers have 8...



