We recommend and sell the IQ Panel 4 in all cases, but in general in your case, PowerG would be best due to the additional range.
Sensors do not communicate with multiple keypads. The main panel houses the wireless receiver. It should be centrally located in a place that gets good cell signaling.
PowerG sensors have about 4 times the range of other RF sensor types available for the system.
If you have hardwire sensors, you can reuse them with a hardwire to wireless translator.
You would only be using the wired sensor circuits, which would connect to the takeover module. The above thread has options for the IQ Panel 4.
Bluetooth and Geofencing are two different things.
There is bluetooth disarming, in which the panel uses bluetooth connection of your phone to automatically disarm from Away. It shouldn’t have any impact on other BT devices.
Geofencing is a location service which uses the phone location for reminders/notifications.