unfortunately, the techniques you are trying in order to get access to a dormant Github account are EXACTLY the same ones that github gets spammed with every day by bad actors attempting supply chain attacks. You don't have anything that proves your identity any more than any rando on the internet in Github's eyes at least. Everything you have presented here may be convincing enough to me, but probably not to GitHub's opsec policies.

Also suppose you Facebook account was compromised, that bad, sad for the person affected. May cause some media attention if the person was famous.

But if the right GitHub account is compromised, we could see massive supply chain issues. Or a big important web service with millions of users affected.

The downside of making a wrong call here is just really really big.

There are real businesses being deployed from GitHub.