"Authentic" is best for name.
I tried to think a lot of names. But it confused because I tried to mix your name , your sisters name, Germany, etc. But please allow me to focus on just your concept "kodawari". I agree the original idea of ramen coming from China. So my idea is 'authentic' ramen cooked by Chinese. But in terms of business, please use advantage of Japanese image. So my idea is Japanese words meaning "authentic" which "HONKAKUHA". Not sure German could easily pronounce it but its meaning is very positive in Japan anyway.