[cyrano]

If I was to set up a system like this, I'd install Reaper on a computer for recording over the XR18's USB connection, close to the XR18.

Then enable the web server on the recording Reaper for remote control.

Control it all from some device with a decent web browser. An iPad, or whatever computer you've got lying around.

The big problem with the Raspberry Pi is that it's ethernet port runs over it's one USB connection. Limited performance, not enough to transfer a lot of channels.

I don't know the Banana solution, but it seems tailored for a Banana Pi. Some models of the Banana range offer "real" ethernet ports. And IIRC the performance is a lot better. Possibly this wouldn't work on a "real" Raspberry Pi.