That was a bit of an overwhelming amount of information. You are measuring the ribbon cable running to the carrier if I am not mistaken. This buffer you speak of is on the carrier itself, not in the printhead? This is a huge amount of information an I think that if it is correct it is very useful. Maybe this will be the stepping stone to how the printheads themselves are controlled. It is the last step before the signal goes to the printhead.
Do you use an ordinary Arduino for measuring or an Arduino based logic analyzer. Have you ever heard of the teensy? It is Arduino compatible (though also bare metal programmable) and it runs at 72Mhz (overclockable to 96Mhz). It has 256kB of RAM and is perhaps fast enough for analyzing the signal going to the carrier.
I can’t wait to see more. This printhead also has CISS system cartridges and is therefore interesting for 3DP printing. It should also be similar, so knowing how this works might help decoding other printheads.