Good stuff. I once read an article claiming the Spear of Lugh was a harpoon. Can't find it now and I doubt the story. Still the whale hunters were a fairly advanced bunch for 5000bce. A sea full of mammals could support a large population I imagine. When you bring in the Siberian herdsman it does open it up to the transcendental, which I think is necessary for a culture to grow legs so to speak i.e. to be influential outside the physical domain. For nomadic heredrs that was a wide enough area already but quite possible their shamans had visions and sent people off in various directions.
I am guessing these ancient people of the north would be as much mongoloid as they were caucasian. Laps and native americans being more closely related to present day Siberians and Mongols than they are to Nordics. I could be wrong but that is where I see the main influence coming from. Indo-europeans or nordics do seem to have originated around this time but I don't think thye would be so wide spread so quickly. basically the further we go back the more of an illusion race becomes.