I'm not sure about trusting the channel scan feature...it's had a history of some strange results...@tony had some comments on it here:
I think the Hue bridge can live about wherever you want it to, I've moved it around to different Zigbee channels and it never seemed to care. So I'd prioritize the C8 (which seems to be pickier) and then give the Hue bridge the left-overs.
One thing to consider is the double-luck voodoo pairing method...not saying you should have to do this, but it has shown some success w/difficult devices:
