Yes, that is all correct, with the note that the firmware does not have a mode that directly supports a clock spanning two units; you will need to play with the firmware to get it to do this function. We would recommend that you leave the Chronodot on one, and designate that as the controller, and have it send serial display commands to the second unit.
Yes, you can potentially run from a power supply and switch. The red Alpha Clock runs at 5 V, and the blue/white version runs at 9 V.
