However, I'd like to point that following your "Subjective truth is where one places one's mind", Dobson can be regarded both as Ueshiba uchi deshi and not as one at the same time, depending on the various "subjective truths" around. Both positions (Kisshomaru saying there was not uchi deshi and Dobson Saying he was one) are true.
Sure. See also Ledyard Sensei's post about Saotome Sensei introducing him as an uchi deshi, despite having said that the uchi deshi system is impossible in America.
One of the first lessons one learns as a writer is the extent to which viewpoint defines a story -- whether fiction or non-fiction. That's just as true in the real world as on the page. Even the "objective" truth that journalists and historians seek is going to be defined by the sources they are (or are not) able to consult.
When one considers a figure like Ueshiba Sensei, one also must consider the difference between history and myth. Though myth may not reflect objective reality, it still describes a different kind of truth.