Then there is the other side of the war, the Pacific theater. I don’t think any events in Europe regarding Hitler (or even Churchill) would have affected the decision by Japan to annex Manchuria in 1931, China proper (at least as much as they could get) in 1937, and then to attempt the quick strike at Pearl along with the dash to the oil-rich Dutch East Indies in 1941.
WWII, at least in the Pacific, was pretty much going to happen regardless of events in Europe. Considering the culture of the Japanese (essentially controlled by the military leaders) at the time, I don’t think the change of any single person in Japan (even the emperor considering the Japanese military could and did replace emperors when convenient for them) could have altered this course.