This is a misunderstanding of the nature of the burden of proof of the type that the analogy of Russell's teapot
was developed to address. In short, it is not necessary for a skeptic to disprove your assertion. It is necessary for you to prove it (as distinct from provide a suggestive, but ultimately incomplete and inconclusive assemblage of evidence that tends to support your argument). You have neither proved your theory nor disproved the counterarguments.
The counterarguments are, for the most part, not bald assertions that you are wrong. They are either alternative theories which may or may not address particulars of your theory, or specific assertions that your theory has holes of both evidence and method in your argument sufficiently large that it remains unproven. These leave you with the option of showing the alternative theories to be false or unlikely in the first case, and of filling in the holes of evidence and method.
Like the other individuals you name in your post, neither you nor I witnessed or have hands-on experience with the skills of Ueshiba Morihei, which means that any argument about the precise nature of those skills is either based on videotape, written description, or hearsay. In the first case, different viewers may come to differing conclusions -- and there are also technical issues like film transfer rates etc. In the second and third cases, both written accounts and hearsay need to be exposed to a number of filters: Who wrote/said this? Who was the reader/listener? What was the context of the statement? What was the agenda of the speaker? These are all legitimate questions that may cause us to give more or less credit to various statements being introduced as evidence.
You cite a number of comparatively exerienced people who find utility in this work and who see a clear continuity between their understanding of Ueshiba's aikido and what they develop in this kind of work. That's useful information. It is also useful information to be told by comparatively experienced people that there is clear continuity between Systema and Ueshiba's aikido, or Contact Improv and Aikido, or verbal conflict de-escalation techniques and Ueshiba's aikido, or Non-Violent Communication and Ueshiba's aikido. Continuity is not identity. Congruity is not identity. Complementarity is not identity. Relationship is not identity. Sydney Bechet is not Louis Armstrong.
The nature of the argument in favor of your theory is like that used in a civil trial -- you are arguing that the "preponderance of the evidence" is on your side and your disputants don't have a similar weight of evidence in favor of their counter-arguments, therefore they should accept your argument.
This is akin to saying: "you can't prove your theory so you must accept mine." What you're failing to acknowledge is that continued skepticism in the face of incomplete information is not only a reasonable position, but may be the soundest position of all.
The above goes to the basic principles of theory formation and evaluation, basic concepts of relatedness and identity, theory falsification and its implications, and the need to examine evidence critically, because this is where the fundamental problem with both your theory and your presentation of your theory appear to lie, based on your summary above. One needn't go beyond that point to identify the structural issues with your argument and your understanding of what it means to "prove" something.
On the other hand, if you could just lighten up a little bit and acknowledge that while you haven't proved your case, rather more gently point out that you still have a circumstantial and suggestive case which is worthy of further examination and archaeology, you might have a defensible position.