What is the best way to create a custom package that configures other packages?
Antoine Beaupré [ Editor ]
In short: don’t do that. It is actually against the Debian policy for a package to modify other package’s files (section 7.6.1), so you’ll have very little success going that route, or at the very least: getting it into Debian. This is also “the wrong way” of doing things because, as you said, the configured package will not call the configuration package so that it can update the config files.