So why don't we get some ideas going about how to do this
I would suggest populating "Document number" with a short ID based on book/chapter, and for "other" documents simply being unique. This part of the ID should not change with translation, so we don't have to worry about it being updated when the file is replicated for translation. If the existing file name prefixes fit the bill, we would have "0202WG3".
The version would be taken from the Alfresco version, and is not recorded in the file on every edit.
We can put the target language in meta-data too if we want it to show up in tool tips or whatever. Language is a suggested value for User Properties; use the same two-letter code as we are in the Alfresco directories.
So, a translation might include an introductory passage that states, "Based on document 0202WG3-en-2.2, with some unique material ported directly from the zh-ch-2.7 that has not found its way back to en yet. Mostly synchronized with en-2.9."
As you see, several documents might be referred to with ad-hoc classifications as to what the relationship is, so I would not include such details in meta-data. However, the author might set up alert dependencies with the various other versions to be apprised when they are updated -- that would trigger on a new version existing, so would not be based on the version number, just the Alfresco document path.
This and other translation notes could be placed in a standard location with a unique paragraph style.
