I agree. Elon is pretty influential and recently his tweets about few countries have increased their stocks. For instance, Etsy and dogecoin rose because of Elon's interest.
Yup. Now imagine him saying "I've bought the dip. Who else is with me?" That's gonna raise the prices even higher.
Similarly, any influencer could just manipulate the price to his/ her liking with necessarily buying BTC. Basically a whale.