This is clever. Putting a bounty on an issue like that to spark user interaction. Good job GHI.
Something I didn’t understand about the led driver. It needs 4 pulses on the Input to realize that you want to latch? If so, and the devices are daisy chained, then how is the data line on the first chip being toggled, as to indicate to the second chip when to latch?
I say, put put a DS1054Z on the device to see what data is actually being received.