Earlier quoted context omitted.
Finnish is an absolutely atrocious language to learn for most people (unless you are already familiar with learning a language with a completely different root, and even then). That part will be hard. I can't comment on the practicality of surviving with only English (or even Swedish, which most of them speak due to historical factors that I will politely gloss over), because I haven't tried.
I have lots of non-finns at my work who speak very little finnish. They seem to do fine. On the other hand integration to finnish society might be bit of a challenge unless you happen to find a sweetheart here. "or even Swedish, which most of them speak due to historical factors that I will politely gloss over" Most finns _don't_ speak Swedish, or it's very limited. It's a second language in law only because Finland…
Initially Germany and Soviets made the Molotov–Ribbentrop Pact to divide the Europe. Nazis would get Poland and Soviets would get Finland etc. They were agreement at first, so Nazis stayed away for the Winter War (1939-1940) and Finland had to block attack on their own since most of the Europe was allied with Soviets or Nazis.
Later in the following Continuation War (1941-1944), Finland asked for Germany's support when they tried to reclaim some of the areas Soviets had previously taken, including the city of Vyborg. German sent some arsenal and troops from Norway. I think the number was 40,000 compared to 500,000 Finnish troops.
So I think it wasn't that much of a "strong support". Also the German troops didn't have the tactical skills or right equipment for long lasting forest/winter warfare, so they weren't that effective either. They were used to Blitzkrieging everything.
Most of the German troops were stationed in the Northern Finland and once the peace was found with Soviets, Finland had to fight the Germans to get them out of the country. Along the way, the German troops scorched everything they came across on their retreat to Norway.