Bob,
after some further looking at your very nice photograph, I can add some further details. Although, it is stamped 1906, I believe it is a wee bit earlier. The officers‘ sword scabbards are still not blackened as per AKO of 26 June 1905. His Majesty is flanked by Generaladjutant, Generalleutnant Dietrich Graf von Hülsen-Haeseler and General à la suite Kuno Graf von Moltke. Note General von Hülsen-Haeselerś Star of the Hohenzollern House Order with Swords worn on the upper right chest; this was awarded on 27 January 1904 which further brackets the time frame of the photo. Oberleutnant Prinz Eitel Friedrich in the uniform of 1. Garde-Regiment zu Fuß is standing next to General Graf von Moltke. Unfortunately, the details are just not clear enough to definitively identify the two Flügeladjutanten but if I were to make an educated guess:
the mounted adjutant would be Major von Friedeburg (at first glance one would think the tunic is the light blue of a Dragoner-Regiment, but I think his tunic is just a little faded) and the officer to Eitel Friedrich‘s left is PLM winner Hauptmann Graf von Soden.
Regards
Glenn