It seems to me that in order to have this discussion, we have to ...
Read everything on Aikido Journal - particularly the interviews of deshi pre/post war, read all of Peter Goldsbury columns, read Chris Li interpretations, find everything the founder ever published, said, was heard to say and the interpretations of first handers that were present. This is the baseline.
For those of us unable to read the original documents we have to rely on the translations of others (see PG columns for things to be aware of in this effort). We must also be cognizant that some interpretations and recollections are 'colored' by the times and context of the interview. In addition it may well be that the choice of terms used by the founder was purposely to obfuscate or overly generalize to address a wider audience (even those not actually practicing aikido) in order to spread the principles
Be aware that there are documents that are not publicly available. The founders library at Iwama sat untouched for many years (anyone that has seen that collection can comment on the size of the contents for reference). I only have third hand info but to say the room was packed would be not an exaggeration.
For my own bias I place extra weight on the story and implications surrounding the demonstration in from of the emperor and contrast that with most every other public demonstration - the difference is quite informative IMO.
Also vexing to me is the Kano Jigoro comment to the effect "that is real judo" contrated when finding comments like "that is the founders aiki" - all is not as it seems at first, second or even third glance and even concentrated effort is difficult.
The moral of the story seems to be that if one is not responsible for ones legacy then that effort falls onto the shoulders of others - they may not have a clear understanding so many details and vital info gets lost in the transition. As more of the 'old guard' fades into history the likelyhood of any certainty of slapping a label "authentic Ueshiba aiki" on anything becomes more and more difficult. In the absence of first hand accounts proclaiming a definition of "authentic Ueshiba aiki" then all we have are innuendo, circumstance, and best efforts. To be sure humanity has gotten along for millenia on flimsy 'proof' woefully short of 'modern' 'scientific' proof of certainty in most every field of knowledge.
If we are not interested in 'proof' then what are we arguing about? Why are we holding such a high standard of 'proof'? Are we willing to acknowledge and accept that at some point our demand for proof cannot be fulfilled so we must take some things on faith? Scientific certainty, beyond reasonable doubt, weight of circumstance, best guess on current understanding, Billy Bob says so.
Something to ponder ... 1000 years from now what will constitute proof of "authentic Ueshiba aiki"?