Thank you for your reply-- you got me to reread Seila Law v. CFPB and I now agree with you. The fact that the CFPB had a single officer was clearly important to the outcome of the case.

I agree with the outcome of that case, but don't think it goes far enough. Scalia's dissent in Morrison v Olson seems like the best understanding of the Constitution's requirement that "the executive Power shall be vested in a President" and that "he shall take Care that the Laws be faithfully executed." To Scalia, the President cannot be deprived of control anywhere a "purely executive power" is exercised.