Oh, as for the Picts and Celts question, the Picts, we can be pretty sure, spoke a Celtic language, and therefore are Celts in the only sense in which that term is at all meaningful. Their "racial" background is undetermined, and will probably remain so, and I really can't see that it matters much. "Celt" is more of a cultural and linguistic grouping anyway, and a pretty loose cultural one at that.