First of all, great thread! I think you put it together nicely. While I think it is good, I would never steal an idea from anyone. I have no way to prove that obviously, but I hope you can take my word for it, all of what I wrote was original to my own ideas.
To your last point. He never implanted any abilities in anyone, that is not how I presented it. Do you not find it funny that what is basically Chakra personified is "harnessed" and then the idea of ninjutsu and ninja came to be?
Thanks, that means a lot coming from a person of sound judgement like yourself. You had more than enough ideas for your own thread, anyway, and it's very thought-provoking.
I mentioned the Sage not awakening chakra in other people purely to illustrate how it seems unlikely that the Sage was incapable of even using ninjutsu, when other people (those he taught) already posessed the CAPACITY to perform the ninja arts. I'll grant you that he was VASTLY weaker and less skilled before becoming a Jink, probably outshined even by average ninjutsu-specialists in the modern Elemental Countries.
It is strange, but it's clear that Chakra and Demons are interconnected. Jinchuuriki posess huge chakra-pools. The Bijuu appear to be MADE of sentient Natural Chakra, and the rise of chakra in human beings is connected to the Natural Energy of the World becoming sentient. So I think the Sage, now literally OVERFLOWING with the stuff, merely guided people on how to better use ninjutsu, the simple beginnings of which he may have learnt from them in the first place. Hand Seals, for example, are not very fitting for someone who was supposedly a monk. An eastern mysticist of some sort (or wannabe one) seems like he could have taught the Sage about those, and then the Sge spread them to the rest of the world as a concentration aid.
What do you think concerning my points about whether the Sage was an Uzumaki or a Senju?