Can you provide a reference that it was the founder who did the renaming?
Hmmm intersting. I will try to find a reference but who else would have it been? Shioda and other pre WWII uchi deshi referred to it as Ikkajo and then all the modern aikido styles including Aikikai and others referred to it as Ikkyo. Is it that much of a stretch to assume it was Ueshiba?
I will do more research to find a reference if one explicately exists.
Thanks but even if he didn't rename it then my questions above still stand.