WASHINGTON — The Federal Reserve is facing a significant change in leadership that goes beyond the installation of a new chairman. It is also awaiting the appointment of two other top officials who will play a crucial role in shaping Fed policy. President Trump, who has already nominated Jerome H. Powell as the Fed’s next chairman, also gets to pick a new vice chairman. But the other open position, the presidency of the Federal Reserve Bank of New York, is not Mr. Trump’s choice to make. The...