On whether or not he owns bitcoins, it's possible without it being made public. Berkshire Hathaway has previously requested that some of their holdings not be made public by the SEC, without any public news, there can be no certainty.
He can also of course have a private wallet.
Its still possible and we never know whats unpublished. People will probably track and try to find out what it is doing with bitcoin and of course the news circulating in the media may not be 100% true. I find it hard to believe that he will never try to invest in bitcoin, which today can still be said to be a very profitable investment asset. I think he know, but guessing that he own some bitcoin is also not the right thing.