It appears that it's Giuliani.
Former New York Mayor Rudy Giuliani is the leading candidate to be Mr. Trump’s nominee for secretary of state, people familiar with the matter said, a move that would elevate a well-known national figure to become the U.S.’s chief diplomat.
Mr. Trump’s aides have also considered former U.S. ambassador to the United Nations John Bolton as a possible candidate, but the close relationship between Messrs. Giuliani and Trump was a major consideration, the people said.
Intelligence Expert Mike Rogers Leaves Trump Transition Team Amid Shake-up
I wouldn't be surprised to see Bolton as an advisor.
Also, Ben Carson turned down the offer of Health Secretary. He's kind of whacky, but I like him personally.