From all I have read, and there is not much information from that period as it was kind a prehistorical, the idendity of the German tribes hadn't been finished then. Many attributes of the Germanian tribes come from centuries later.

The line between Celtic and Germanian is very thin, there are many similarities. Also the areas must have been mixed.

The Cimbri and the Teutons on the mearch become a mixture anyway. They must have been attracting many other people from other tribes abd cultures.