There are lawyers that specialize in digital assets in Korea, but they are rare. Maybe a lawyer aware of securities and finance would be best.
In anycase, I advise legal consultation before mentioning about legal actions. And yes defamation and privacy are important. Even others mentioned 'doxing' isn't necessary. He can make a private list and at least verify first.
I do think he can prove he owns darth knight by signing a message. However proving he doesn't own bittrix is more difficult.
In anycase, I feel that is irrelevant. He said it's not his and we have no reason to believe it is his. Better to take his word on it and help him out. If anything else, it's the right thing to do.
I don't know if he can get his assets replaced, but this is a bad time to be responsible for freezing him out. The reasons for the freeze in general are iffy given the balance of control for steem is not even close after Hive was made. There is a gap in the timeline that is obvious here.
Anyway, I hope it can be resolved out of the legal system. Usually only lawyers win.
I'm so tired of the arguements that the list is based on a mathematical formula (more so Hive's list that excludes airdrop). It's not like some universal law. Any variable can be added such as 'include accounts only if created before HF21'.
The drama needs to end. I still have vain hope for win-win.