Hi there,
I'm based out of Florida, US (-5 GMT) I am well versed in linux automation, but more specifically in the last year I have been focusing on Raspberry Pi based products. I have wrote similar scripts in the past, both for myself and for commercial use.
I can have your requested script completed tonight for testing, I do want to clarify that we're checking the /boot/ partition of the SD card correct? That's generally where automated installers are placed on boot.
One final question: Do you want the script to overwrite existing passwords and configurations or only the default ones?
I look forward to working with you,
Michael