Possible simple high availability set-up, questions

I have a secondary Home Assistant Green which I intend to use to make it easier to get things up and running again if my primary one fails. In the event of a failure, I would just move the Sky Connect dongle to the secondary HA Green, power up, and restore my latest full backup to it.

Now to my questions:

(1) The obvious way to do this would be to use the same IP address for both HA Greens since only one would ever be running at any time. My question is: if they had different IP addresses, would the restored image work or not? Does anybody have practical experience of doing something like this?

The advantage of having the secondary HA Green at a different IP address would be that I could play with it in various test scenarios, alongside the primary one, while also having it quickly available in the event of failure

(2) I described the situation where the same Sky Connect is used on either HA Green. What extra steps would be needed if each HA Green had its own Sky Connect dongle but the backup from one was used on the other?