By now you are probably wondering why you got no replies. It's because what you're asking for here is a professional review of your own system design. A hobbyist might have an opinion or two, but may not want to share it because of how extensive your system is. A professional wouldn't want to post suggestions because, well, he's a professional. Sort of like trying to diagnose a sick patient via email. And a pro won't want to give away free advise when that's how he makes his living.
You ask for the best possible sound system, yet you don't define a budget to work in. Based on the numbers you post, the "Best Possible", in the absolute sense, would mean you are way low in budget. I doubt anyone would expect the "Best Possible" from ceiling speakers. You put speakers in the ceiling because you either have no choice, for aesthetic reasons that win over sound quality, or ignorance. Or, in your case it looks like you may have some free speakers around, but if your goal is "best possible", even if speakers are free, if they are wrong, they are just wrong.
Please don't be insulted at my comments, but if you're really going to go to all that effort, hire a pro to at least consult. An A/V professional charges between $85 and $150 per hour. Hire him for an hour or three to walk through your place and work with you. Then at least you'll have a qualified professional's opinion instead of unqualified random posts.
What you're doing here is asking, in a free forum, for free advise, on which to build an extensive AV system in what seems to be a rather significant home. Unless the home was free too, you might want to consider paying an A/V pro at least what you'll pay a good electrician, and get some good, qualified advise.
