According to Summers & Mangold (pp. 226-27) General Max Hoffman stated that AA was the AN in 1927.
"One of the people Hoffman spoke to about the affiar was Baron AMagnus von Braun, father of the famous space scientist, Wernher von Braun. The baron testified that General Hoffman, died in Jluy 1927, shortly after making his curious assertin, and just before he was due to visit Anna Anderson. He had been reported as saying: 'I don't have to see her, I know', as though he had inside information which had come his way years before. As one of Germany's top commanders who had been in charge of the 1918 peace negotiations with the Bolsheviks, he may have had access to privlieged intelligence about German efforts to help the Romanovs, an what became of them. But here we are left speculating - in the general's published papers and diaries the fate of the Russian imperial family is notable only be its complete omission."
This is the only reference I have found on Hoffman so far.
Felix Dassel was a soldier wounded in 1916 and treated at the Tsarskoe Selo hospital. The hospital was under the patronage of Marie and Anastasia who ofter visited there.
"Dassel got to know htem well, and after his discharge the tsarina appointed him their escort. When he learned about Anna Anderson's claims, in Germany 1927, Dassel devised a way to test her on that specific period in the real Anastasia's life. Before meeting her he wrote down a series of minute details about those hospital days, details only the real Anastasia and Maria could have known. He sealed the notes in an envelope and had them put in a a safe by the Duke of Leuchtenberg, who was at that time Anna Anderson's host. He then met and questioned the claimant, making deliberate mistakes to discover whether or not she would correct them. The claimant passed the test with flying colours. she correctly identified 'Mandrifolie' as her sister Maria's nickname. She put right Dassel's deliberate error of placing the billiard table at Tsarskoe Selo upstairs - it had been downstairs. When Dassel mentioned that she and Maria had come to the hospital every day, often with their brother Grand Duke Alexei, she accurately pointed out that they had only been able to visit the hospital two or three times a weekm and they had never brought Alexei along. The clincher for Dassel came when the Duke of Leuchtenberg referred to an old Russian colonel, who Dassel remembered well. in Dassel's words:
'...she was seized suddenly by a little laugh, a little laugh which rang in my ears, a trifle muffled, a little uneven, but exactly, exactly as of old...I could not reman seated, I jumped up and grabbed the back of my chair. "The man with the pockets!" she said. "The man with the pockets?"
'Yes, yes. He had been given that name - and naturally I had forgotten it a long time ago. It was Anastasia who had given it to him, because the warrior from the front, impulsive and blunt, always natrual, had often forgotten etiquette and spoken to the grand duchesses with his hand in his pockets...Abruptly I recognized her, I was convinced."
I believe Kurth also talks about this episode in his book, but I can't find my copy right now.

more to come....