You may think that Bernadotte was right to obey the letter of his order but the essential point of the whole controversy is : Did Bernadotte on October 14th hear the sound of the guns of Auerstedt ?
It is difficult to believe that he spent the whole of that day without the faint idea that a desperate battle was raging not more than 7 miles away to the north.
Under such circumstances, he was inexcusable not to tear up his writtens orders and march to the sound of the guns.
Concerning Davout’s ADC, you should read captain Trobriand’s report in Foucart (p. 694).