Can't speak to 1 & 3, but as for 2 - I'm running my 2 channel/HT fronts with a FetValve 550, and the center/surrounds with a 240/3, without any problems. Speakers are all Song Tower QWT w/domes. Surrounds are SS Is.
I'm sure there's enough in the know to address 1 & 3 more than adequately. Hope this helps a little.