Plausible. Also wonder if having such huge war losses created a demographic void.
Hm, I guess that depends on how you're qualifying/analyzing the demographics: at the broad end 100% of the German/Japanese/Italian citizens are their respective country's people, but if you were to increase your granularity you might find that (for contrived/unverified example) more Protestants were killed in Germany than Catholics, which would result in a shift in religion if big enough.