Jannis is becoming pretty popular in Germany, as well as
Jannik and spelling variants of both names.
Lucas is over the top popular, but is mostly
Lukas. Wanja is pretty uncommon, I have never met anyone called Wanja. The same with
Prisca which is not at all a common name in Germany. Fränk has to be some odd variant of
German Frank, probably a nn or else a Bavarian/Austrian variant of the name. I have never in my life met anyone called
Kiri here in Germany, it's very uncommon, although
Kira is pretty well-known and I know two girls called
Kira. Joschi can be a nn of many names, such as
Joshua,
Joseph... But I'm not too sure of this because the name is pretty uncommon in Germany, i.e. not popular. I only know one young actor called Joshi or
Yoshi, but then again:
Yoshi is also a Japanese name...