RBK 752 Guest Network question and general information

Yes, the Guest WiFi network broadcasts from every Orbi unit (router and satellites).

All Orbi units broadcast on the same 2.4G and 5G channels.

All WiFi networks broadcast on the same 2.4G and 5G channels.

(primary WiFi, Guest WiFi, and the new optional Internet of Things (IoT) WiFi.

Exterior walls are a common location for the router because that is where the Internet Service Provider (ISP) located the cable modem or optical fiber terminator unit (ONT).  Obviously, about half of the WiFi coverage area is "outside" which is not a great situation.  Moving the router to a more central location would improve service, but is simply not practical for many users. (myself included.  My router is in the corner of the building next to the wall.  Thus I beam almost 3/4 of the router WiFi "outside".  This old two story house is not conducive to installing data cables, which is why I went from the R7000 to the Orbi system back in 2016.)

I would expect about the same coverage with the Orbi setup.

By the way, the EX8000 can by used with the Orbi in the same way it is being used with the R7800.  WiFi "extenders" are a useful solution to connecting devices that are not mobile. (such as thermostats and beds)

My 5 1/2 year old R7800 and Ex8000 combo having router issue lately (disconnecting connections and forcing password change when logging into it)and I picked up a rbk752 last night. I read manuals online but could not get my answers clearly before I open it. I work remote several days so performance is a concern.
1) the guest network does it transmit from satellite as well the router? Or just the router? Yes.
2) does guest network use same channels as main network? Yes. 
3) does the satellite broadcast on same channels as router (ex8000 is a different class and allows this as well as unique names on extended for guest network). Yes.
Lastly can I expect same coverage in 2400 sf home with Orbi? Currently router is one 1st level exterior wall and extender was in a room off kitchen. 25 to 30 ft away. Also have basement and second floor. Basement is unfinished and not included in square footage. Yes. 
The reason is I have some devices like humidifier/ thermostat/ sleep number that run exclusively on 2.4 and I created up a guest network in 2.4 ghz network for these that was outside of existing mesh. I had a heck of time with sleep number bed connecting previously.
New version v7.x FW has support for a separate IoT Nework SSID that you can configure for all of your IoT devices. 2.4Ghz or 5Ghz. https://community.netgear.com/t5/Orbi-WIFI-6-AX-AND-Wi-Fi-6E-AXE/New-RBR750-RBS750-Firmware-Version-7-2-6-21-Released/td-p/2333937/jump-to/first-unread-message