Re: Ueshiba + Chin-Na?
We'll probably have to agree to disagree on this one. As you say, "but there's no records to prove much of anything" ...
I've looked into this question off and on for years, and even made some comparitive studies (spent a couple years playing Hsing I and Pa Kua, as well as a couple of other Chinese vairants), and while I don't doubt there was SOME cross-pollination, I'm not convinced there was as much as some folks would like think.
Hell, depending on how far BACK we go, heck, the Japanese were mainlanders in the remote past anyway, and yes, there was more commerce (trade, religion, etc) through the years than is apparent, but nonetheless, to say that aikido (or XYZ ryu jujutsu) originated in China is, to me, a bit of a stretch.
Far more evidence of Okinawan-Chinese intercourse (literally and figuratively) and cross-pollination of the 'te' systems by Chinese sources (pretty good evidence that the Ryukyu ruling class actively pursued training in both Chinese and Japanese martial systems through the years) and thus, SOME Chinese influence as the Okinawans were integrated more deeply into Japanese society, and thus, their budo.