Yes, the same Wi-Fi connection is required to pair. All Wi-Fi extenders should be unplugged during the pairing process. After pairing is complete, the smartphone can use any internet connection (3G, LTE, Wi-Fi) to operate the app functions.
Astute Devices only have 1 switching channel, it can, however, connect multiple appliances, but will only switch as 1 unit. If for example a geyser and pool pump are connected to the same ASC, both will switch ON and OFF simultaneously. The CBI Home App can service multiple Astute devices. If you wish to control multiple devices independently, install multiple Astute Devices.