The actor who plays Gunnar, Riley's dad, is a well known singer/songwriter in Iceland. He plays a musician in quite a few shows, one of them the well known Game of Thrones. Though he does play some instruments, a piano double was used.
The scene where Wolfgang and Kala speak in the rain was filmed in the patio in front of Barcomi's Deli in Berlin Mitte.
WWNDD? means "What Would Nancy Drew Do?"
In one scene, when Nomi is hacking dr Metzger's phone, you can see that name of cafe is "Atlas cafe". Atlas Cafe is a actual, popular cafe in San Francisco
The festival that young Kala is attending is the Festival of Colours or Holi. It is one of the oldest festivals in the Hindu religion.