Really depends on what and where.
The only nations who can liberate puppets are communists, and the only nations who can liberate sovereign nations are democracies. So, I wouldn't see the CSA being a thing because an Axis player would only be able to puppet the entirety of the United States. The only other option is the USSR invading the USA, and since their puppets are more or less just government changes rather than actual puppetry, they would simply change the US government to be communist (and knowing the communists they would not want to split off the CSA over keeping the continental USA intact boarder-wise).
Korea is a different matter. Though historically you have the North and South Korea divide and the East and West Germany divide, and how Paradox said that would not be a feature (at least a basic feature, maybe a special event solely for Germany and Korea), it would make sense that any Korea released would own all its territory. Communist liberation would liberate just "Korea", but it would have the north Korean flag and be called "Democratic People's Republic of Korea" or something. Allied liberation would liberate "Korea" as either "Korea" or "the Republic of Korea" (probably just "Korea").
Pakistan is another one I can think of. Given that the British Raj gets to be its own thing at all probably means there might be things tailored to India in regards to events. Pakistan was its own story of very complex circumstances, and since religion doesn't play a big role in the game I would see any liberated India having the entirety of India, Pakistan, and Bengal. I don't really know the reason of releasing Pakistan (which would include Bengal) without bringing up the animosities between the Hindus and the Muslims, which could very easily not happen, as easily as it did.
The African countries are tricky. They are drawn on colonial boarders. Axis countries cannot liberate them because they are still colonies, but I don't know what the Communists would be able to do. I doubt the Communists would just let the Europeans keep their territory, but at the same time I doubt they would force the Africans to maintain their current meter-drawn boarders. I could see any and all releasable African countries just having modern boarders for the sake of convenience because there are no agreed-upon boarders in Africa, while colonial boarders are at least internationally recognized.
Vietnam, Cambodia, and Laos should be easy to release.
Seeing from the World War Wednesday it is pretty clear the USSR really isn't dividable, at least not yet (maybe Ukraine, Belarus, and Siberia will be releasable in the future).
Northern Prussia is also a matter. Historically, Russia directly got northern Prussia, and still owns it today. Not sure if there will be a possibility to release it as is own thing, if it will be forced to be given to Russia, Germany will be allowed to keep it indefinitely, or if it will just be given to Poland.
The breakup of Yugoslavia should be pretty easy, maybe use modern accepted boarders, but there are disputed claims in the region so that will be a challenge. Then again, the breakup of Yugoslavia isn't really relevant for WWII because it stayed united.
I feel like Scotland and Wales have enough separatism that it should be possible to divide the British Isles between its kingdoms.
Dutch Indonesia might be another issue. Historically, it could be released as the unified power it is today, or it could be divided among its islands.
Israel is its own whole can of worms because of how many countries have claims in the region, and against common belief EVERY claimant has legitimate claim. It may not be worth the political controversy. The region is too important to be left out, but I trust the developers have made a good decision about it. Might be best to use boarders as were declared in 1948, since it wasn't recognized as a country yet, and has defined paper-noted historical boarders that cannot be argued against and are irrelevant to modern politics.
I can't really think of any others, especially for alternate history. Reason I heard Manchukuo wasn't in the game was to help the Japanese AI, which is a fair enough claim because the Emperor of Manchukuo had very little power over his resources. It could be a thing, the ability to play as Manchukuo and reform the Qing (since the Emperor Puyi still had claimancy over the title of Emperor of China, and Manchukuo had claim over the rest of China), but it is not worth getting in the way of Japan's ability to be an East Asian powerhouse if the AI is really bad (and we are still in the century where AI is stupid).