So are you able to automatically bring up kits using some sort of program change message when sequencing and controlling the A4 with some sort of MIDI sequencer, say, the OT?
i don’t thinks so, but kits are linked to patterns which can be ! you can send the data of a kit into the AF using sysex, but that’s not what you’re after
If you have program change messages enabled you can use them to switch pattern slots. So if you save your kits appropriately to pattern slot numbers you can switch using this method.