Yeah. I don't think we assumed that every Dick and Jane on the Paranet knows about the cold iron thing.

You can find out about the whole cold iron thing on wikipedia, of all places.
And every gamer who has ever played in a WoD Changeling game knows about it.

How more commonly known can one get?

I envy your beer selection Carabas.  I lived in Ansbach when I was in the Army (way back in 89-91) and have fond memories (if somewhat blurry) of Bavaria.

Back in 89-90 is was in the States attending high school.
And, while we have a great beer selection, I am not a beer drinker. I prefer wine and cocktails...

Lots of pissed off ghost potential in Dresden but Munich is a better crossroads city IMO. 

Funny, "crossroads" is sort of one of the themes of the city. We decided on "The bridges over the Isar (the local river) do not only connect the two river banks." Starting from there, the city has a whole lot of places where you can crossover into the Nevernever. There even seems to be some sort of portal beneath the city leading to the Outer Gates or beyond. And we decided that at the Marian Column (the exact geographic center of Bavaria) all Bavarian Ley Lines cross. Probably a feat of supernatural engineering changed the flow of the ley lines when the column was raised.

So, "crossroads" is written all over the city.

My players and I have already started to dresdenfy Munich, Bavaria.
Now all I need to do is figure out how to include the Oktoberfest

Bingo. A DF character is composed of 7 aspects: the ones you get from the backstory (5), your high concept (1), and your recurring trouble (1).

Can I invoke my recurring trouble to get re-rolls or a +2 bonus? Or can it be only tagged and compelled?