To answer your Questions:
The German Nehrim does have the Nehrim.esm and the Nehrim.esp, nothing else, the Nehrimenglish.esp is just for the Subtitles

Well for the Translation question:
Arandor wrote:You may translate Nehrim in any language you want 
You can also see the full conversation
here 
Edit: Replacing the voices isn't always a great idea because the German voices of Nehrim were performed by a Professional Voice acting Team of 56 Voice Actors from a Recording studio of Berlin, and I think the most Voice recordings of Free2play mods/games aren't that great
It lies in your decision, maybe you can bring out a Chinese subbed version and later on a Chinese dubbed version
I mean I mostly watch Animes with Japanese language and English subs because I like the voice acting more
