If the Awen/Aum connection isn't one you've come across before, I'm delighted to play the messenger in this case. When you say that you've documented chunks of unrecognized Indo-European myth in Iolo's writings, is there a book in which you did so?

I'm not sure about the standing stones you refer to, but I'd like to know. As for burial mounds, I presume you mean Kofun, the famous keyhole shaped burial mounds that pepper the entire island of Japan. Does the keyhole motif also appear in Britain and Ireland? (Or are you referring to something else?)