

It’s not the most secure but I just set up a port forward in my router to the device with the emulator on both sides of the connection. When you’re done playing make sure to remove/disable the port forward. You connect to the public IP and port of the other person. Shouldn’t be any different than making local lan play work at that point. Your latency is pretty much just whatever the transfer time is. This does require both of you to know how to set that up in your router and basic networking knowledge.











The emulators software should handle that(gets the player 2-4 inputs from over the network). I play Tetris Attack with my sister sometimes ~2000 miles apart which is an old Super Nintendo game. No such thing as network play on that console.
The network features on the emulator should work locally or remotely. You just have some extra steps like I mentioned in my first comment to make it work remotely. If you have a spare device to run two emulators locally I’d start with getting it working in your own house before trying to walk a buddy through it remotely.