Hi fearFX,
1. No, but you don't need a VP150 for that room size and listening distance unless you want extremely loud playback levels. The VP100 is just fine for an application like yours.
2. Perfect height.
3. On the side. Set up a good 5.1 system with the surrounds located where they're intended to go, just like in large cinemas. You can try a couple of extra surrounds on the back wall for 7.1 later on and see if there's any improvement.
4. It's very hard to make comparisons of bipolar front speakers with direct-radiating models. In the old days of 2-channel stereo, I used to love bipolar speakers because with large acoustical works (orchestral, choral, jazz, big band), bipolars gave a big, diffuse soundstage (with somewhat vague, murky imaging) that more closely approximated what I heard in real concert halls.
But bipolars, in my judgement, are inappropriate for the front channels in surround systems. You want precise imaging at the front so sounds move with screen action, and the M22s will deliver that as well as a nice sense of depth if it's in the original source recording. The surround speakers provide all the ambience and spatial properties, and the Axiom quadpolar QS4/QS8s are exceptional in this regard.
One of the virtues of compact speakers like the M22s in smaller rooms is the versatility of placement. Because they don't have deep bass output (the subwoofer supplies that), you can actually put them on an open bookshelf. Nor do they interact with nearby room boundaries as much as floorstanding speakers.
Regards,
