Sam, though missing the latest features, the Yamaha RX-V659 is a great AV receiver, and does have one of the best amplifier stages of units in its price range. It will have no trouble driving the B&W DM601’s, however once a subwoofer is added, it will be best to set them to “small” in the 659’s setup menu. During the time that these were current, I worked at an audio dealer that sold Yamaha and B&W. I heard the 659 with many different speaker systems on display and in customers’ homes as well, and the absolute best sound for a surround setup was using 3 pair of DM601’s and subwoofer. This provided a perfect timbre match for all 6 channels. I totally agree with RW’s advice that timbre matching is VERY important, and other brands should be avoided. You could just add a pair of 601’s and CC6 for the rear, or use 3 DM601’s since singles show up on ebay at times, or sell the CC6 and get 2 more pair of 601’s. Timbre matching is for the 5, 6, or 7 channels, and not the subwoofer, so it can be any brand.
The Pioneer SP-BS22-LR is a great budget speaker, however, has a 3db less sensitivity than the 601’s, which will decrease the overall dynamic capability of the system. The result of this 3db difference will be the same as using the 601’s on a receiver with half of the 659’s power output. In your room size, it will be an advantage to use the higher sensitivity speaker. Dynamics and deep bass are important for a good home theater.
As an alternative to the 601’s in your price range, take a look at the
Hsu Research HB-1 MK2. It has excellent reviews and its sensitivity is 4db higher than the 601’s, which will result in better dynamic capability compared to the 601.
Yes, it is possible to mount speakers to the ceiling. There are many different types of mounts available. Just make sure you choose one with an adequate weight limit for the speaker, and attach securely to the ceiling joist.