The best way to debug this now (and avoid confusion) is to debug the PICs separately from the Core modules.
In other words, it doesn’t matter which “Core” you use to upload, only that the PIC ID and the ID in MIOS Studio match.
So, since the master Core module is known to work, try uploading MIOS and the application using J11 set to 1 and always putting the PICs in the master Core module (far right). Once you get MIOS 1.9f installed on each PIC, you can check it’s working by looking at the LCD connected to the master Core module, it should show “READY.”
What’s confusing me now is that you list PIC #0, #1, #3 and #4. The IDs should be 0,1,2,3 and go in Core modules 1,2,3,4 (my fault for labeling the Cores this way! I should have labeled them 0,1,2,3 like the PIC ID).
FYI repeated upload requests (like what you’re seeing for PIC ID#3?) means there is no MIOS installed. Once MIOS is installed, then it only sends out one upload request on startup.
So what you can do now is try to upload MIOS and the testtone app onto each PIC in the master Core (Core 1). Then once you know all the PICs have the application, try (for example) PIC #0 in Core 2, 3, 4 (changing jumper in J11 to match) and then testing both MIDI Out (upload request), LCD, and MIDI In (try using the debug functions in MIOS Studio to send the LCD some text!)
btw I think you are a bit confused about the PIC ID… this is “burned” into the PIC when you burn the bootloader and doesn’t change by uploading MIOS or applications… it’s totally separate from the Core that you plugged it into. The Core modules don’t have an ID, they’re all the same, connected to the same MIDI In, with J11 controlling which has MIDI Out, the only difference is three of them don’t have LCD backlight and only the master Core is connected to the 8x Banksticks (patch memory).