Skip the Cambridge. It's overpriced and didn't get any better "marks" than the Pioneer Elite SC-61 or 1222K. The Pioneer 1222 at a bout $550 or so (on sale at newegg a lot) would be a great choice. 4 ohm certified and a nice feature set for the money.
But the Emotiva setup would be killer too if you can afford it.
Don't waste your time and effort in bi-amping. It does nothing when the speakers have active crossovers.
Let us know how you like the speakers when you get them. They seem like a great deal.
Klipsch RF-62II, RC-500, RS-400, SVS PC12+,
Def Tech SC8000
Harman Kardon AVR 1600
PS3, Apple TV, Sharp 70" Qattron