@RailwayHacker I'm not part of the Wigwag team, but some of those questions seem to have fairly straight forward answers.
What happens during power outages? (is it detected/reported?)
---- It could only report if you created a rule in the software, and had power and a connection to the outside world i.e. Cellular or POTS phone.
-What happens when power comes back on? (is it detected/reported?)
---- I can only imagine that you will be able to create a rule in the rule based system that could send an alert when power is restored or the relay starts back up upon receiving power.
What happens if a malicious person jams the Wi-Fi / Z-wave / ZigBee / Bluetooth? (is it detected/reported?)
---- If someone jams one of those signals and you have a device on that network, I am sure that you could create what is called a heartbeat monitor that would alert you if the connection goes down.
What happens if the internet connection is cut? (is it detected/reported?)
---- Create a rule that if your internet goes down it sends an event through Bluetooth or wifi to a cellphone.
From the looks of the rules that can be created, it seems that we are only limited by our own imagination.
Can you recommend a backup power (UPS) solution? I would recommend something that could power your modem, router, and relay at a minimum so you could get some sort of notification without using a cellular connection. I personally have my stuff on an APC UPS and it powers my modem, wireless router, and charges my fail over WAN connection through a cellular hotspot. If my cable is cut, my router auto switches to my cellular hotspot and don't loose my internet connection. It all depends on how fail proof you want to make your setup and how long you want it to last before power is restored.
I hope this info is helpful for you or anyone else.