That was so cool!
I too went on this adventure with my laptop. Sadly I hit a wall while reverse engineering the ACPI stuff. With no logs, error messages or tools on the Windows side to intercept the ACPI events, I was at a loss but eventually gave up. Massive respect for managing it with your own laptop!!
I did manage to reverse engineer the keyboard's LEDs and drive them from user space! Studied the kernel to make a contribution but decided not to do so when I saw comments saying it is better to keep functionality in user space if at all possible.