Re: ueshiba and chinese martial arts
From what I have read, it is highly unlikely that O Sensei learned any CMA. One reason is that relations between the Japanese and Chinese peoples during that time were not good. Also, a great deal of his time in Manchuria was spent hiding and running away from aggressive locals.
An explanation about similarities between Japanese and Chinese (or other countries') martial arts is that the human body will only move in certain ways. As such, there are bound to be similarities.