I'd say mint is great for non tech people (90% of the time it's the DE and GUI apps that are important rather than the distro, but mint has good ones by default). For former windows power users I'd recommend CachyOS or Fedora. Either way, you can boot from USB for any of these as a live demo; I have images for all 3 + memtest on my ventoy USB.

Guess it's too late now, but mint has an option for automatic updates.