Actually, I think that France is a fairly likely place to go communist. Their
communist party was
immensely popular after WWII and they were also very pro-soviet at that time.
As for Italy, I think it's important to keep in mind that Eurocommunism only showed up in the 70s. If the PCI manages to take power before that, than I think Italy will likely join the Eastern Bloc. They could certainly also go down the Yoguslavia path, but for that they need a Tito-like figure.
I could the southern communists taking power if the early RoK is even worse than it was IOTL. Provided they can sort all of their issues with Kim, which can likely happen with Soviet and Chinese mediation, we coul certainly see a pensilula-wide DPRK.
Now regarding Japan, I think that even if the Japanese continue the war the most that the soviets are likely to get is Hokkaido. Given that, any eventual "North Japan" is probably going to be very small and likely also very poor, so I don't know if the Soviets would be that interested in keeping it as satelite. It certainly still happen though, and maybe, who knows, there's a scenario in which the soviets can grab most of the tohoku region. In that case you could get a larger North Japan
However, when it comes to getting a communist Japan, I think there's another possibility that is fairly doable but I never really saw explored. If the post-war American occupation of the country goes bad enough, I could see a home-grown communist revolution happening there. We could have a unified communist Japan.
Now, of course this requires the Americans to screw up really, really badly, which they're not really likely to do since they knew what was in stake...