This mistake only occurs in the self-hosted repo, which contains very little code. All of the "real" code is in the other four repos, each of which have their own LICENSE file that did not have this mistake.

Yes you can. If someone claimed "I can use it because they accidentally published the wrong license and swiftly corrected it", that wouldn't hold in court.

Would you have any precedent for that? I think in most of the world, that would hold in court.