You don't necessarily have to reduce to 7. Let's consider what you're trying to do with the new house layout, remembering that none of it is built yet:
An Atmos-capable Home Theater setup in the Living room
A Stereo music setup in the kitchen
A Stereo music setup in the bedroom
If you consider them as separate zones, we're just pointing out that you don't have to tie all of that functionality to a single AVR. In fact, it can be more expensive to do so, and we gave some options.
Considering the Home Theater zone by itself, you described 3 front speakers, 4 surrounds in walls, and 2 speakers in the ceiling, for a 7.2.2 system, needing a 9 channel AVR.
Using 9 channels, you might consider putting 2 less surround channels and 2 more ceiling channels. The overhead effect would benefit much more going from 2 to 4 than the base surround effect would be lessened by going from 7 to 5.
A 9 channel AVR could do either, and candidate AVRs include the Onkyo TX-NR797 and Pioneer VSX-LX504.
You could go down to 7 channels and a 5.2.2 system to save a some money, or you could go all-out with an 11 channel system, with the same 7 speakers you originally described, but with 4 ceiling speakers for an 7.2.4 system, but that's a bit more expensive.
On to the Stereo music Zones. You could treat them being controlled separately with 2 devices, or from the same device.
Sonos would have you use an Amp device to power 2 speakers in each stereo zone, at $650 each, one for each setup, before considering speakers.
Denon Heos and Yamaha MusicCast have similar devices for slightly lower, but similar prices at $500 and up. Play-Fi has a much wider variety of manufacturers and devices, but still relatively expensive. There may be some at $400 and up.
If you used Heos, your AVR would have to be Denon to tie them together. For MusicCast it would have to be Yamaha. For Play-Fi some Onkyo and some Pioneer models (including your VSX-LX103) are compatible.
Convieniently, all of the AVRs are also Airplay 2 compatible.
With the VSX-LX103 you already have, you can power both the kitchen and bedroom speakers using Zone 2 functionality if the wires come to a common location.
If the internal Play-Fi functionality can only serve one zone, you could add a Phorus PR5 Play-Fi streamer for $30, then use it for Zone 2.
If for some reason you don't want to use the LX103 in this role, you could use either a multi-channel amp in a central location, or a stereo amp for each zone, combined with PR5s for <= $150 for each zone.
Then with a Play-Fi app and the appropriate remote control apps, you could control everything from your phone as long as everything is using the house network via wifi or ethernet.
If you use a Play-Fi AVR such as the Onkyo or Pioneer mentioned before in your home theater combined with these suggestions, all devices would be Play-Fi, and you'd have Sonos-like functionality that costs quite a bit less.
Even if you used another brand AVR in your home theater, The LX103 and pretty much any other AVR you'd pick would be Airplay 2 compatible. They'd show up "natively" to Apple devices and phones and Android phones with an Airplay 2 app.
In the case of mixed brands, you'd need a different remote control app, and the streaming services might differ slightly, but you could still control it all from your phone.
So, figure out your Atmos setup, and if you want the other zones controlled centrally or locally, and a Play-Fi compatible setup may be practical and economical, but if not, you could back into an Airplay 2 compatible setup for less money than a single AVR that tries to do it all.
Originally Posted by Tech Neeq
Thank you, gentlemen!! Both comments were very helpful. So, instead of 9 speakers connected in the main HT room, reduce it to 7?
A total of 9 speakers connected to the AVR.
2xIn-Wall (instead of 4)
Bottom line: Don't use the receiver to play music in the other 2 rooms (a total of 3 zones) - or - use it for only 2 zones and an 2-ch amps for the other areas. Another option is to purchase another AVR. I'll ponder on these ideas and also wait to see if others have a different opinion.