I could imagine a couple ways of doing it. One is that the Bela mini-USB connection shows up as a virtual network port (as well as a storage device). I believe these drivers are built into most desktop Linux systems; not sure if that extends to the Organelle or not. Try the procedures at beagleboard.org for getting set up on Linux to see if you could log into Bela from the Organelle. If that works, then you could exchange OSC between the two.
Otherwise, your options would be old-fashioned 5-pin MIDI (with USB adapters as necessary) or if Organelle has any extra GPIOs or analog signals, to wire those to the Bela I/Os.
