This will kind of require maybe a rework of the mod where there will be events where the Japanese get new generals in their conquests (much similar to how they conscripted Koreans and Indonesians into the Japanese Imperial Army). This would greatly expand the already limited general list.

If I remember correctly the Fuherreich has it where throughout the years and in different conflicts, it allows for "random generals to appear." Kind of what I thought of for this mod.