Thanks for posting this update. The transition of Fabric from Gerrit to GitHub certainly facilitates this process making it easier to add the translations. There's alot of good translation work that has already been done by the team so we are well positioned now to use that with the process you are proposing.
I agree that creating the new Fabric-i18n repo with folders for each language is straightforward and should be easy to manage.
Thank you for putting together this proposal and we look forward to sharing more on one of the Contributors Calls.