Amazing post Michael! I have been following your story for years.

I have also a similar project backing, but not as technical as yours. I use also Raspberries for Smart Kiosks that are set to be in restaurants and increase the demand of the most convenient dishes at a time with great photography.

I see that you think now of Debian packages as an optimal way for installations in your project.

What would you say it is the best way yo keep a Raspberry system "auto-updated"?

PD: My skills are way lower than yours. I use mostly Ruby scripts (SystemD) to contact a backend in Rails.