Interesting stuff, thank you. After doing a bit of troubleshooting on the command line I eventually worked out that the problem I have is that there was no chip on the ribbon cable at all - the eink driver was trying to load the waveform from eeprom, failing due to no eeprom and loading a "default" waveform.
Ripped open the Kindle again and saw the distinct lack of chip on the ribbon cable. Contacted the seller and they've admitted sending me the wrong screen and have sent a replacement, complete with eeprom.
I am hoping for a plug-and-play transplant next time. It's weird that on some of your screens you have to go through this process of extracting the chip data from a similar screen. It's my understanding that each screen or batch of screens can be subtly different, and the waveform data for that particular screen is written to EEPROM at the factory to be read by the device at boot, so the device knows how to address that particular screen.
A little bit of evidence I found to support the above - when I tried your procedure of booting up with the old screen attached and then hot-swapping to the new screen, I found the colours had returned to normal, but text was a little darker than normal, and menu ghosting was VERY apparent, things just generally looked uglier. I am pretty sure that is due to the waveform of the old screen not being quite right for the new one.
I'll report back when the new screen eventually makes it's way over from China
