2.
I've already purchased two Furutech GTXD-NCF duplexes with matching NCF
covers and GTX Wall Plates. Does each duplex need its own breaker to
isolate from the other?
No. And you only need one outlet.
Let me expand on that. Ideally you only need one outlet for one condititioner, everything plugs into that. This minimizes ground loop issues to pretty much zero. It is nice to have one free outlet to plug whatever into. Lamp, whatever. Main thing is you want everything that is a connected together part of the system to all be plugged into just the one circuit. If you can get a conditioner with enough outlets to do that, fine. If you have something like a lot of subs to plug in, those are less particular with power they can plug straight into the wall, but they still are part of the system and must be on the same circuit to avoid ground loop noise. Keep this one simple principle in mind it will avoid an awful lot of grief.
My architect says our main panel is getting
crowded and is urging me to limit to two breakers for the audio rig.
First, you only need one breaker for the whole system. Second, if you do need to add breakers and no space get a thin twin. These are two breakers designed to take up half the space of a normal one. Take one of your non-critical circuits like a bathroom/bedroom and swap the two breakers to one thin twin. Then use the free space to do the room.
3. I will be purchasing some kind of power conditioner/distributor. Can digital be plugged into the same conditioner as analog?
Yes.
5. Would I plug my tube integrated directly into the outlet or can it go to a power conditioner?
Either way. As long as you do as above, no problem. If your conditioner is any good however then it will sound a whole lot better plugged into the conditioner. Any time you hear anything like this conditioner is good for this but not that, run, this is what we call a crappy conditioner. The good ones are good for everything, period. Right now Decware has one, that I haven't heard but looks to be very good indeed.
https://www.decware.com/newsite/ZLC.html Keep in mind that since this is sold direct, like all Decware, you would at least double the price to find anything comparable at retail.
6.
If I buy speakers that each have an onboard Class D amp for subwoofers
that need to be plugged in, can they be on the same circuit as the power
amp?
Yes. They should be. See above.
I'm considering getting two single outlets closer to the speakers
to avoid a long power cable run to each of them.
I would avoid this. Use passive subs like I do powered by a Dayton SA1000 for all the bass anyone could ever want and run ordinary cheap 14ga wire off a reel.
Lastly, did your electrician know this stuff and advise you or did you have to educate yourself completely?
Electrician? We don't need no steenking electrician! This whole system, everything you see and a whole lot more, is all me. It ain't rocket surgery you know.