Hi Betrumka,
Welcome to the forums. =) Interesting read, many questions isn't there. The Hitler rein is such a horrific part of history, yet an important one as no one should ever forgot the horrors that happened, the victims of the Holocaust and their families, nor the many that gave their lives in the war.
Perhaps the alleged book that brothers are writing will provide some answers and put to rest some speculations or affirm them? I say alleged as until the book is in print and/or a publisher announces it's intended release date etc, no way to know for certain if the book will be completed and/or published. I suppose they will need to provide some documentation or form of evidence for some of what they intend to tell, as going just by their word alone still leaves room for more speculations. I'm guessing there will be some who believe what they say and others who will refute it, in particular if their research has noted something different. Although why William Patrick opted to change the name to what he did may only be based on word alone.