Woads, the only term I've heard used for them are the celts that supposedly used woad dye to make their battle tattoos. In the movie, the "Blue Demons" are Woads.

Æthelflæd, Lady of Mercia..She is a saxon warrior woman.
Mainly celts and norsemen. Now that I think of it, youre right about the time in which certain things were discovered...I don't know.

For Guenevere, in the Goddodin, the earliest referrence to Arthur and Merlin, there is a woman who fits the description by the name of Winlogee, it may not be her but it may be.