Interesting. You can get a very small
PCB that is a bluetooth serial terminal.
You can also get a
VFD with a built-in serial controller.
It seems to me that hooking these together would give a person a remote bluetooth display which could be controlled via the empeg's serial port (which was connected to a bluetooth adapter).
That doesn't solve the problem of sending button presses and knob turns back to the empeg though.
I'm going to bed. Interesting stuff. Sometimes I wish I'd been an EE instead of an ME.

Jim