I'm totally going to steal that idea sometime!
As for advice, if there are wizards in the group the neutrality that Richard mentioned is going to be a HUGE factor. Remember that Injun Joe sat back while European invaders slaughtered his people with guns and biological warfare. Maybe even some on the council might think that a participating wizard needs to be stopped for fear of the ramifications.
Richard also mentioned Kemmler which is an awesome way to go.
Hitler was known for seeking out occult items in the real world. Maybe that can play into it.
I would also like to introduce something else. The following is not meant to be offensive but instead shake up actual history into something unexpected. Let me give you my brother's statements on what really happened in World War II. (Click only if you can take things with a grain of salt.)
Nobody really understands the motivations behind World War II. The truth is there was a hideous zombie outbreak. The governments of the world (and the churches) refused to let the people know what was really going on so they fabricated a war. Some of the select few decided that something had to be done and their had to be a cover-up. Based on the prior Great War, many lies were fabricated. Yes, in some parts real Allied soldiers were in combat with real Axis soldiers but that's wasn't even half the fight. Most of the fights occurred against soldiers and zombies. These soldiers were convinced by their superiors that they were enemy combatants-- I mean, the supernatural doesn't exist. Yes, some Jews were rounded up and there was persecution. Those bodies in the mass graves, though, were mostly disposed of zombies. The stories of bodies in the ovens, or the testing of gasses was for testing weapons on zombies or disposing of them.
In the end, somebody had to take the fall and be blamed for everything. Hitler chose to be the skapegoat and be forever labeled as one of history's greatest monsters.
The point of what I just gave wasn't to insult the people who suffered horribly in history, but to take what we think of historical fact and turn it completely upside-down. It's like how Abraham Lincoln: Vampire Hunter enlightened us on how the Civil War was begun to fight vampires.
What if Stalin was actually behind everything, sending demons in to possess certain high-ranking officials and cause hysteria in the masses? What if Hitler was seeking out occult objects because occasionally he was able to fight his possession and wanted a way to find freedom and end the atrocities his country was committing?
What if everything the NAZIs did was for a hidden reason. The next spoiler is if you haven't finished Changes...
Remember how they wanted to sacrifice somebody of Ebenezer's family line to kill him? What if rounding up the Jews was something similar that started with an excuse to round up the family of a powerful practioner but wasn't exactly sure where to start? What if the rest of the Final Solution just happened to be a side-effect of hunting this family?
What if Churchill wasn't human? Why would he try to keep England free? Maybe the Axis were being controlled by a malevolent force and if the UK were to fall, they would have free reign over Stonehenge? (Stonehenge, of course, is one of the most powerful objects on the planet. Your players don't have to know why-- it's a guarded secret.)
Also, wizards + WWII planes = comedy plane crashes
Have you read Cold Days? Winter's motivations get some exploration there that might throw all of that into context.
Cold Days Spoiler:
Considering Winter's job is fighting Outsiders...what if the Nazis, or more specifically the Thule society or some other occult body within the Nazis were summoning up Outsiders? That'd get both the council and the Winter Knight involved.