Not to be a thread killer. Not to take anything from Mr. Li's brilliant research on the subject.
But a lot (not all) (maybe unknowable) of the founder's teaching ability and who taught what to whom, and also who went to who for what, including lineages up and down the time lines of aikido and daito ryu is laid out in Ellis's Amdur's book , "Hidden in Plain Sight". Having just finished reading it in what maybe the first of many times( yes my head is still throbbing), it is illuminating a little bit about this very subject.
What I took from it in first go around, is separation between the teaching of technique or waza and that unseen quality (hidden in plain sight) which is most likely internal strength, internal power .
The founder's younger days it seems, or so I am told(which are provable because of meticulous Japanese record keeping) were filled with a wide ranging vocabulary of techniques and teachers and arts.
And on that front it seems when time came to write it down, Saito sensei filled the bill quite nicely and almost 1000 techniques (with aiki ken and aiki jo added in) were codified in Iwama. A veritable perfect score of Aikido SAT vocabulary or technique. Pretty sucessful there.
On the other hand, the ability to teach and then do the waza on uncooperative opponents or downright hostile foes(using IP or IS) seems to have been either lacking on the part of the teacher AND OR or the students . How many of the 3rd generation students and teachers in Aikido are taking on all comers in this manner? ( like to study with you
Clearly there were deschi of O'sensei saying in his later years, " we didn't know what He was talking about". And then there are the films of people bouncing off him , and what appear to be shock waves being generated far greater than what seem possible for a 5 foot tall and change man.
So there is the showing and telling of this quality. Teacher taught, but not do A + B +C and you will definitely arrive with D and also D by the way is tapping into the infinite power of the universe.
You know of course that as soon as that last sentence left my fingertips, I realized that he also did say exactly what D was........
Back then to the original point, it is all out there, I never had a lesson with O'sensei, maybe a couple of classes with direct deschi of his, and there was no mention of anything other than technique, once I became an earnest student more was discovered and more also was thought to be given.....
Its a moot point, and I think it is more up to oneself now.......
I hope that I did some justice to Ellis's book and Chris's research, not to mention many others, and eagerly await clarifications, and corrections as it will be awhile before I delve into this rabbit hole again