I mean I remember reading a book where Lenin heavily denounced imperialism, and Lenin was an influential figure in the USSR and communism worldwide, so were these invasions seen as imperialist by communists abroad?
For the Soviet invasion of Poland, there's this article linked to in the FAQ: "What was the reaction of the Communist parties of the world when the Soviets attacked Poland along with Nazi Germany in 1939? Did it have a similar effect to the Hungarian Revolution of 1956?" at https://www.reddit.com/r/AskHistorians/comments/3ejnh7/what_was_the_reaction_of_the_communist_parties_of/ctftedc/ , answer by /u/kieslowskifan
This is just a quick introduction, not to discourage further discussion, especially since it doesn't cover Finland. Further questions, data, and debate are welcome.