I'm assuming that the OP is posting the question in good faith - Musk on the other hand has a track record of disclosing private information for fun/retaliation

I'm assuming that the OP is posting the question in good faith - Musk on the other hand has a track record of disclosing private information for fun/retaliation, whether or not it's legal for him to do so. "Assume good faith" doesn't mean you have to overlook everything about the situation when discussing the situation. I'm not asserting that Musk would do anything illegal in this case, just that there's a reason the Twitter board may not want to give him private data. It's not obvious that he wouldn't disclose, either directly or implicitly, anything he's given.