Note : Making this new post just in case other was overlooked/misunderstood somehow.
For Japanese, the Onna-Musha replaces the Crossbowman, including the location in the build menu, so it should use the same hotkeys as Crossbowman for Producing / Upgrading Onna-Mushas.
Unfortunately, this was overlooked outside of all the other fixes to hotkeys for patch 9.2.628.