I don't have a lot of correspondence from April, however, Grenier's "Étude sur 1807, Manoeuvres d'Eylau et Friedland" states that the Emperor transfered his headquarters to Finkenstein 1 April 1807.
The 23rd of March, the disposition of the army was: Guard massed about Finkenstein, the cavalry reserve to the north as far as Elbing, 1st Corps stretched from Braunsberg to Halland, 4th Corps from Wormditt to Mohrungen, 6th Corps from Guttstadt to Bergfried, and 3rd Corps from Allenstein to Osterode. Gazan, St. Sulpice, and Grouchy were concentrated nearby.
The rest of the chapter describes correspondence of intent to his Corps Commanders and to his adjudant commandant Guilleminot "to find a good military position for an army of 100,000 men to occupy to the right of the Saalfeld lake and left of the side of Christburg..." he was evidently content at this time to take up a defensive posture while waiting for the reduction of Danzig. He warned of a possible attack of the Russians over the Passarge and a debarking of troops near Danzig (which did take place). There wasn't a lot of movement from the Winter Quarters by the 1st, 3rd and 4th Corps until the first week in May.
Your ADC's commands from Duroc seem to be in keeping with those passed by Kutusov through Nadezhda Durova who acted as his ADC before Smolensk.