arden.ballard

That's correct.  I don't have paging to all bedrooms.
My house isn't so big that just yelling from the top/bottom of the stairs doesn't work.

That said, I have some touchpanels waiting to be installed in the kids' rooms when I get a bit of time.
RyanE

Total?
-Wall Mount Living/Hall (One mentioned above)
-Wall Mount Office (Probably the most redundant, occasional intercom use)
-Wall Mount Master (Could do without especially since adding a portable - this will likely move to front door for music control garage and front as well as security))
-Wall Mount Theatre/Basement (just outside theatre door which is also right at the stairs leading down - Similar scenario to the first one)
-Wall Mount Deck Door (also used a lot, to select music out there)
-Portable Living (would be used more but not a great place to put it since furniture changes)
-Portable Master (Used a lot)
-Portable Theatre (Also well used)
-Portable Kitchen (purely there because of intercom and camera view while cooking, and because I had it (V2))
 
As for what I would recommend? One per floor wall mounted in the most high traffic location. Plus one each (wall or portable depending on scenario) for the biggest movie viewing/music listening rooms.
For me if I had to do 'essentials' only (remember that I have a lot because I tend to upgrade a lot, re-utilizing screens elsewhere) I'd probable have one per floor wall mounted centrally, one at the deck door (we spend a lot of time in the backyard) and one portable for the Theatre.
Preference would be adding a portable to Living and Master to the above
Note that I could do without screens in other TV locations because I do have onscreen available at every TV for movie selection.
 
Apps for me are purely used outside the house unless I'm testing for issues. It's just slower, and as I mentioned, my phone goes out of reach once I'm home - I'm "connected" enough all day thank you very much.

C4 Touchscreen advantage:
-Always on C4
-Faster (even then on an ipad Pro with no other apps added). This comes into play in particular if you have large movie or music databases you want to browse)
-They are 'always' there. Especially wall mounted one, but event he desktop versions aren't going to be taken for any other purposes (ie charging, gaming)
-Not dependent on underlying OS, so not affected (or broken) by changes made to andriod or iOS updates
 
Now whether or not these advantages apply to you, you find important or not is your own decision.
I have several screens in my own house, and they get used ALL the time - I never use the app on my phones or tablets unless I'm testing things.
For me, my phones go on my desk once I'm home. I don't carry them on me all the time, so they are just not conducive to use.
More so - the 'wife' factor. My wife nor kids (yet) will go and get a phone, tablet or otherwise out to control anything - yet they'll walk up or grab a dedicated TS all the time.
I'm not saying fill your house and every room with screens, but having a few C4 screens in well-thought out locations can be a huge improvement over tablet use.
I'd say my one TScreen location I implemented years ago that is on a narrow wall that is at the centre of my house, at the nexus of my kitchen, dining. living and hallway to bedrooms is the single best individual thing I've done for my personal C4 system. That screen ahas be replaced (upgraded) 3 times now, going from 7" to infinity edge 7" to V2 7" to T3 10" - not a single regret.
 

Just like you, I absolutely cannot justify the price of a one-app C4 tablet which I need a total of 8-10 in my house. I've been researching alternative touch panels for a while now. The obvious difference in your proposed setup, which was a killer for me, is the phone being a stand alone unit vs. flash mounted on the wall (please advise if I'm missing something as I'm very much interested in the topic as well).
Another option I'm considering that you might be interested in is fire tablets. I placed an order, will let you know how that works out. Fires (as opposed to Ipads, don't ask me why) have Skype with auto-answer function. Thus you can video/audio chat with any room just like you would using intercom (the receiving party doesn't have to press anything to hear you or to be heard). You can place group calls as well. Another Fire benefit is that they just launched an update that integrated Alexa. So with a push of a button (not voice activated) you can ask your tablet to turn on your C4 devices (or so I hope, my Echo Alexa could certainly do that). This might be very handy in a guest room especially if you have elderly visitors.