Any information on countries fighting in theaters they're not located in, such as Chinese fighting in Europe or French fighting in the Pacific is also welcome.
EDIT: By location I mean the location of the main geographical area of the country, so excluding things like colonies.
I'm not quite sure I understand you second question; the French did fight in the Pacific since they did have colonies there, hence they were "located" in that theatre. Same thing applies with the Dutch, British etc.
Also for clarification, are you asking about people of Japanese, German, French, etc. heritage or people who were fighting on behalf of the Japanese Empire, Nazi Germany, French Empire, etc.?
IJA soldier Yang Kyoungjong was not ethnically Japanese, but a Korean. He was captured by the Soviets at Khalkhin Gol and eventually ended up in Ukraine, where the Wehrmacht captured him. Finally, American paratroopers captured him in Normandy