Stephen K. Bannon, one of Elon Musk’s most vocal critics, said he was advising the president to cancel all of the tech billionaire’s contracts and launch several investigations into the world’s richest man. “They should initiate a formal investigation of his immigration status, because I am of the strong belief that he is an illegal alien, and he should be deported from the country immediately,” Mr. Bannon, the former top aide to President Trump who is now an influential ally and informal adviser, said in an interview. ...Mr. Bannon said the Trump administration should also investigate Mr. Musk’s drug use,...