Chances could be that Communism might exist in Strike Witches universe, but unlike the real world (our world), Communism is nothing more than a small fad in the Strike Witches universe, just an annoyance for Senator Joseph McCarthy to bitch about. The way I see it, the Communists failed in their Orussian Revolution in the Strike Witches universe.
The alternate names of some of these countries are real and date back to 117AD like Lusitania, Hispania, Gallia, Dacia, Moesia, and britannia
These places existed and what made up most of the Roman Empire in Europe