First, Thank you K. James for this thread.
That is the way I read it. This should be the only way a different docroot will work. It has to have the same structure (folders) and file names after the pointer.
Did you see my two low tech batch files suggestions to Ivan in this forum? Eloy, or someone with more brains than me, probably has an easier way and hopefully already invented most of the wheel when they created the HTML files.
There are so many redirects in MoodleDocs, trying to figure out what is what for a reasonable min number of pages, will be a lot of work in itself. You might be able to get away with a full copy of the French MoodleDocs as a starting point for a custom MediaWiki but not the en version.
In other news: I did a little work on the Moodle Docs page (given recent posts here), which led me to a "help" page that got me thinking about a page on "Help files" just to assist the new user.