To confirm the EP500 and 600 as well as the 400 all can be daisy chained. For that matter I think all the Axiom subs can be.

As long as the speakers are not close to the ground you should be OK. My M22s resting on my hardwood floor are no brighter than they were in my carpeted HT room.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70