This might be kind of a minor nit pick, but should the scripts in the OpenVPN documentation be immediately renaming a user's zones?
If you want to check for certain prerequisites that's one thing, but just blindly tinkering with existing zones seems a little cavalier.
The UCI firewall config sections are unnamed by default, so naming them changes nothing from the LuCI point of view.
However, this makes easier to read the code and configs and diagnose potential issues rather than just using numeric identifiers.
Obviously, additional steps may be required if the firewall settings differ from the defaults, which the how-to relies on.