As a (sogenannter ) German "specialist" I had a little bit of an advantage and actually knew three of the idioms. A quick check of my book of German idioms confirmed the fourth. I fully agree, however, both that it was a little unfair on those who don't have Brewers and/or don't speak German and, as Whatsthat has posted, that there is an extra word in one of them which is very rarely if ever used.
Whatsthat -- I would love to see your standard of German in all the public exam scripts which I mark. ( Subordinating conjunction with correct word order, I'll give you 6 for both Range and Complexity of language and Accuracy, 6 being the maximum mark. )