Your knowledge is superior to mine in this area Dowrgi.
Knowledge doesn’t belong to anyone, it’s a gift that we should all share. I’m happy that you find what I can share useful.
I do like getting to the heart of words, the etymology, the derivation and the original thought behind, or perhaps within, the word itself because I think that it may teach us a lot. I’m still running with the idea from Julian Jaynes that all words are metaphors and, given that we’re both on our bardic course and journey, I think it’s appropriate on many levels.
I found this interesting site/link re Rhiannon, Rigantona and Epona. It seems quite well researched and there’s also some stuff on Thomas the Rhymer that may be interesting.