sixuality could be an echo or an homage to the first duality. It could also be completely unrelated to the mythos.
Very intriguing.
Though which gender do you suppose fits either Anu or Padhomay? Going the traditional route, which we see all over Earth-culture, I'd say Anu is the more masculine principle while Padhome is feminine. The robust absolute against the gracile void and all that.
Then again, in the Aurbis, both Anuiel and Sithis are referenced as male, while the feminine principle- Nirna, is the mediation of those poles, the gray maybe.