Since I'm stuck at work for the next 12 hours...
What have you got hooked up to what at the moment?
Right now it looks like you have high end and low end components all mixed in.
The Mcintosh and B&W are all keepers of course. The rest I would sell if possible.
You say you need a sub and center. Which speakers are making up the rest of the system?
Integrating a different center channel is not a good idea. I had to and you can hear the difference when the sound pans across the front. A matching center is a must.
More info needed. And no, I'm no expert but have been playing around with HT for a while. Those B&W's would make a great HT setup, just need a matching center. Then you would need some good spkrs for the tube setup.