Yawi – Yahweh , one of those intriguing etymological homonyms ? I know of no connection other than in my eclectic mind.
I enjoy the Solstice celebrations that are mentioned. For me they reach their pinnacle in their personifications of the Christian myth of Christ -winter solstice and John the Baptist – summer Solstice motif. Lots of fun to follow the associations. Christ the Hope eternal in the dead of winter (Sol Invictus). John the Baptist – the eater of the excess bounty of summer honey and locust , rich in symbolism. Making the way straight in the wilderness.
For me these indigenous rituals of our collective ancestral heritage are all prototypical antecedence. Evolutionary expressions of our collective human urge to create abstract and symbolize ourself and our environment physically psychologically intellectually. Lots of fun to impose and discern similarities within our imagination following the trajectories to modern scientific thought. Always keeping the mythopoetic aspect of the creative artistic urge in mind. Science at its vanguard is artistic. We are the archaic ancestors of our descendants.