There are some problems with dates and with nomenclature.
Aikido was not given its formal name until 1942 and so it is difficult to believe that O Sensei was teaching this in Shingu in 1930, after he had already moved to Tokyo. Presumably, he would have been making occasional visits there.
I am quite prepared to believe that Hikitsuchi Sensei met O Sensei before the war, but his teaching of the martial arts to troops in Japan and Korea appears to rest on hearsay and I not found anything to corroborate it after a lengthy search on Google (in Japanese: English is hopeless).
Well, the IAF demonstration will be held in the Kumano Hongu this year and the organizers will be Hikitsuchi Sensei's students in the Kumano Juku. As usual, I will have my pen and notebook ready.