What were my ancestors 2000-2500 years ago?

By that period of time, the Irish were in Ireland, and as the names you give are commonly known to be Irish, it is unlikely that your ancestors participated in the invasion of what became Scotland. Were you descended from inhabitants of the Dalriada, you likely would not have such names.

As for the German antecedants, that is very problematic, as the time period of which you speak was very much in flux, with a Gothic migration south along the course of the Elbe pushing the existing German tribes to the West, where they clashed with the Romans. J.M. Barry was the contemporary English-speaking expert on the "barbarian" invasions of the Roman Empire (not sure when he died, although recently, i believe), and his lectures were collected in a book which i have somewhere at home. The information in the book is not, however, sufficiently specific to identify groups smaller than tribal confederations, such as the Franks--so you might need to wait for someone like Walter to show up to enlighten you as to the Germans.