I doubt it as they have massive border with the Soviet UnionThis doesn't hold if the USSR gives them Manchuria back, though? Wouldn't it be feasible for them to be neutral if that was to occur?
There won't be a Korean war without a Communist government in all or most of ChinaThe better question is, does a rump State in Manchuria hold up? We’re talking about a province right on the Korean border, and you can bet that the UN forces won’t be shy about curb-stomping the NK forces when the worst thin behind the line is Manchuria. The best NK can hope for is a rump State in the far north, and even then, it probably collapses and is quietly repatriated into the RoK, while the world mutters, “Can you believe those assholes?”