Having Stauffenberg as a field marshal indeed doesn't make sense. He should be a colonel, a major general at max.
Stauffenberg, Von Rundstedt and Van Geyte were mayor icons in the Deutschkrieg, where the 'old guard' (Van Geyte, Rundstedt and other non-nazi military traditionalists) led the Reichsfront against the Spartacusbund and NSDAP. Stauffenberg was one of the colonels following Van Geyte, was promoted to Mayor General during the Deutschkrieg and will later be promoted to Field Marshall by Van Geyte (At this point in the story he is indeed Mj.General, but that won't last much longer so get used to Field Marshall Von Stauffenberg
)
In this timeline, 'Field Marshall' or 'Grand Admiral' are also terms that designate political influence, as both Van Geyte and De Nil are military autocrats, who believe that the army (In De Nil's case, the Royal navy) should lead the country. Think of South-American style military junta
http://en.wikipedia.org/wiki/Stratocracy
Before the Revolution, the English Parliament was strongly dominated by Mosley, who, under influence of Van Geyte and De Nil, is much less radical than he was in real life. Mosley functioned as a de facto dictator, with De Nil acting as advisor. The Board of the Admiralty also strongly influenced English politics, and often clashed with the Liberal Conservative government which is now in control with Churchill as head. Thus the Free Fleet rebellion, and the fact that the entire Admiralty opposes the revolution.
In Germany before the revolution, Van geyte instituted Hitler as dictator because he had the support of the population, while a shadow cabinet containing Van Geyte, Von Ribbentrop, Rundtstedt, Rommel, Stauffenberg and other known Reichsfront militants had de facto control over the country. Both the SS and the NSDAP exist in this timeline, because Hitler still held a certain amount of personal power, which grew over time as Van Geyte and his generals left for the Eastern Front, loosening Van Geyte's grip on the regime, as he was focused on winning the war against Russia and Japan.
After Van geyte's takeover is complete, the Wehrmacht for example, will be renamed the Reichswehr.
The entire AAR centers around the conflicting ideas of new and old, where De Nil and Van Geyte represent "old" ideas: Imperial Restoration, reinstatement of the German Empire and Churchill and Hitler "new" ones: Hitler's racial policy and Third Reich ideas, and Churchill his democracy. Our end goal is creating a New World Order in which England and Germany end in a position the US was in after the collapse of the USSR: Great Power status, strong airforce and navy, international cooperation (Oh yes, the United Nations will be making a cameo, albeit
slightly modified) and of course, nuclear capability.
And about how Stauffenberg lost his eye: Seriously people, make something up for yourself. He was cutting a birthday cake in '38 when he accidentaly slipped and jammed the knife in his eye. He likes pirates so he wears a patch. end of story.