Nearly every button or knob on the organ sends NRPN midi including eq knobs, effect knobs and buttons, leslie fast/slow, break and bypass buttons, chorus/vibrato buttons and knobs, etc… These are NRPN and you will need a gig script to re-inject these as CC Midi for GP.
Drawbars, expression pedals and attached footswitches send CC Midi.
Transpose, octave, “play”, “record”, menu direction buttons and buttons that control system functions… these do not send anything.
Lots of internal functions can receive sysex messages too btw.