I'd like Finland to be able to win the Continuation War, via some decisions or events or something - if Finland holds the territory it lost in the Winter War, and the Soviets lose Moscow, then being able to offer a peace, restoring those territories to Finland, should be possible.
From a realism-perspective, there was no reason to accept a separate peace while Germany was winning the war. Depending on what the front would look like, accepting it could well have still been suicide. IRL in 1941 Stalin did supposedly "offer" Finland a return to the pre-1940 borders, in the form of mentioning it in a letter to the US, the contents of which in turn were sent to Sweden, from where they were sent to Finland. How sincere that letter was is dubious. In any case, accepting any kind of separate peace in 1941 would have been suicide for Finland and simply have led to the country becoming a war zone between the Germans and the Russians, and probably led to a subsequent Soviet occupation. Not to also mention that Finland at that point was entirely dependent on grain imports from Germany, without which the country would certainly have faced famine in 1942, something she very nearly averted thanks to said grain.
Sadly the game doesn't really model any of this, so in an in-game scenario where the Germans have pushed the Russians back all the way to Siberia, there could be a separate peace event that gives Finland her pre-1940 borders, all of East Karelia, as well as the Kola Peninsula, since by the time the war would be in Siberia, Finland would for all intents and purposes be at peace, and should not suffer the in-game stability maluses that come from being at war. A Greater Finland would be a fait accompli, even if Finland would de jure refrain from annexing territories outside her pre-1940 borders until a formal peace deal with the Russians would be signed (in-game that'd be a German-led peace conference, or a peace event similar to something like the Bitter Peace). Actually already IRL the country did demobilize a large part of the army from the end of 1941 to around mid-1944, going to a partial peace-footing, since not much was happening at the front during the so-called "Trench War Phase" of the Continuation War.
Nothing to say about your other points btw, totally agree with them.
For those who are not Finnish this might sound strange, but the highest leadership of Finland, while at war with the Soviet Union, definitely did not want war with the USA, whatever some lower ranking officer (even a lieutenant-general) thought.
Which is what Airo is saying. He simply questions the logic of it, since a US declaration of war realistically-speaking would not have made Finland's situation any worse. He is likely correct in this. After all, it wasn't some half-hearted political pressure from FDR on Stalin that saved Finland from Sovietization in the summer of 1944, rather it was Finland's armed forces together with units and much-needed anti-tank materiel from Germany, that stopped the Soviet Karelian Offensive at the VKT & U-lines, as well as at Ilomantsi, in June-August 1944. Arguably impeding American lend-lease to the Soviets might have ended up saving more Finnish lives than not cutting the Murmansk Railway ended up costing.
Finland advanded further than it's prewar borders mostly only on those areas where there was a considerable Karelian (relative to Finnish) population.
The ethnic composition of those territories, beneficial for propaganda purposes as it may have been, was irrelevant to the actual decision to cross the pre-1940 borders; that was done on a purely military-basis. Not that you are necessarily saying otherwise, I'm merely mentioning this for clarification.
