AFAIK, you can’t load A4 kits nor OT parts via midi, no sysex for that. You need to load an associated pattern :
Midi Program Change > pattern change.
Different approach : in song mode, MD, A4 and OT accept Song Pointer Position messages. Theorically you can choose the start of the song and play it on the fly. Tested with OT.
SPP messages with midi controller?