> Would the Japs have turned into the real threat that today’s China turned out to be? <
I’d have to say yes. The Japanese government thought the US would sue for peace right after Pearl Harbor. So Tojo drew up a proposed peace treaty. He wanted (among other things) Alaska, Hawaii, and Cuba!
The Japs wanted it all then. The Chinese want it all now.
https://en.wikipedia.org/wiki/Hideki_Tojo#World_War_II
Remember, that Tojo was relatively late onto the scene, before him, the Japs weren’t so hardcore.