Yes you can connect an external audio interface , I do this a lot for connecting to eurorack (es-8) but you can use any class complaint audio interface.
My initial reaction was that the only sensible thing was to be able to choose it from the menu in the Organelle, but having it as part of an individual patch is actually a really good idea for specialized setups! Gonna have to try this out!
As I don’t have a screen at home, I cannot see if the MOTU Ultralite MK4 works with the Organelle. Has anyone tried this with the MOTU? My first attempt by using -audiodev 7 did not work.