Q2: in order to maximise audio quality
In order to maximize audio quality you would eliminate the processors and multi-channel altogether. In order to maximize audio quality your home theater would be two channel. Sell everything surround, buy more subs. All movies regardless of when they were made or how they were recorded play just fine in stereo. Only the sound quality is way better. Seriously.
https://systems.audiogon.com/systems/8367