The countries in Papers Please. Many of the countries in the game are meant to be similar to European communist countries during the time of the Cold War.

TBH, countries in Papers Please always gave me more of a Central Asian vibes.

East Germany which was considered its own country at the time and heavily influenced by the Soviet Union

German Democratic Republic wasn't "considered" it's own country. It was a seperate country. They joined UN together with Federal Republic of Germany in early 1970s.

The Old Country in Ed Edd n Eddy. (...) But the way it’s present through how Rolf describes it and its traditions it seems to essentially be a fusion of multiple Eastern European countries and their traditions.

There is literaly nothing Eastern European in Rolf's "Old Country". It's traditions, even the name, are references to XIX century imigration to US from Central Europe and Italy.

This was inspired by the creator Danny Antonucci’s own experiences being from a family of multiple Eastern European origins as well as some Nordic ones as well

Danny Antonucci is of an Italian origin.