Just a quick nitpick regarding to cultural/ethnical similarity with Russia: although the Baltic states were part of Russian Empire, the local culture had also strong German influences. Up until end of 19th century the Baltic Germans were the ruling class (although the region was in Russian Empira). So the local culture was mix of German and Russian influences, which makes it somewhat different with rest of USSR states.

https://en.wikipedia.org/wiki/Baltic_governorates

https://en.wikipedia.org/wiki/Baltic_Germans#Russia.27s_Balt...