In the movement to API-2, where should I focus to create a method that will recognize all of a system’s REAL network interfaces and then manage them (one at a time) in searching for a connection (usually IPMI, so NOT mDNS/Bonjour).
To better explain, I’d like to be able to determine the connection between my Pi device and the system the user is connecting with and then set the networking options for that port without the user’s interaction.
I feel like a 63 year old noob at this point 
Well… the Xojo NetworkInterface methods only show you the interfaces that are currently active, that is, connected to something. So you should be able to use that list as a starting point.
That said, at least on macOS, changing network preferences requires at least an admin user, and for good reason. You wouldn’t want an app connecting you to an insecure WiFi network so someone could scrape data from your transmitted data without your knowledge.
To accomplish something like this, I suspect that you’ll need a helper app, probably running as a Service or a Daemon (depending on the platform) that your app can communicate with, but that in of itself may be challenging over different security contexts.