Yes, some Democrats did serve in his cabinet. Foremost among these was former Texas Governor John Connally, who was a friend of Nixon's and whom Nixon even hoped would be his presidential successor.
the Cabinet
No, they already have jobs. However, they can serve on special cabinet committees.
Frances Perkins, who was Secretary of Labor from 1933 to 1945, was the first woman to serve in any president's cabinet.
Cabinet members are appointed by the President and confirmed by the Congress. They serve at the pleasure of the President and can be dismissed or quit at any time.
They have to be chosen by the president himself.
False
John Tyler, Andrew Johnson, Harry Truman, Lyndon Johnson, and Richard Nixon were all vice-presidents and US senators but never held a cabinet post. ( Martin Van Buren was the only man to be the VP, US Senator and hold a cabinet post.)
The US cabinet members serve at the will of the President. He can ask for their resignation for any reason.
Cabinet members do not serve a fixed term. They serve at the will of the President and appointment expires if the President leaves office, but they can be re-appointed if the President so chooses.
Presidential Cabinet Members usually serve for a single administration. There is no law declaring term limits on members but they serve at the Presidents discretion or in other words they serve at the pleasure of the President. He decides who and for how long a cabinet member serves after Senatorial Conformation of course.
Yes, he legally could.
They do not have a term. They serve until they are no longer wanted.