As you state, China is not a communist (or Socialist) state. I use socialist to refer to states with collective/government control of the means of production. Scandanavia cannot be described as "Communist" or even "Socialist" as the term was originally understood. It's a free market system with a large welfare state and government control of certain non-public goods. Scandanavia is far closer to Laissez-faire than it is to the USSR.

China's economic system is sometimes referred to as State Capitalism, though it depends on the sector. Certain sectors are dominated by government owned enterprises (ICBC, Bank of China, CCB, & the Agricultural Bank of China are all majority owned by the PRC government), but others are not.

It is my understanding that of the counties you mentioned, only Cuba & North Korea could accurately be described as centrally planned economies. The collapse of the Soviet Union had a very negative impact on both economies. North Korea's GDP per capita fell be more than half and Cuba's GDP fell by about half.

China thought that it was foolish of Gorbachev to tackle political reform before economic reform. As we all know, Deng Xiaoping did the opposite and the PRC has yet to reform their political system. The fall of the Soviet Union actually led to China seeing the USSR as less of a threat (the two had issues in Vietnam & Afghanistan). Since the fall of the USSR, China's position has switched from one of an American partner against the USSR to an American rival that partners with Russia).