There have been several possible meanings of the word "aiki" over the years. There are older usages of the word then this. What is your point?
Well, you claimed that Deguchi came up with the word, but it has a history before 1922 when Deguchi suggested it, and that has been documented.
Takeda and Deguchi disliked each other, can you really see someone as egotistical as Takeda taking direction? How about people like Sagawa, who pre-date Ueshiba in Daito-ryu but still used the term "Aiki"?
FWIW, there are quite a few martial references using the word "Aiki" made by Ueshiba post-war.