Russia hasn't had the humiliation of the Russo-Japanese war, but OTOH, the question is whether the Russian Revolution of 1905 released some of the steam from the pressure cooker to keep it from exploding earlier or it set the stage for 1917.
My thoughts too - being a BIT more democratic and having a slightly more competent government than that of Nicholas probably helps too, but there are still a lot of social pressures at play and probably too many to stop some kind of blow up around this time.
I'm also curious if there is a significant difference between the Poles and the Finns in terms of succeeding in independence...
Me too - what's interesting is the the Niepokornie generation of nationalists in Poland (roughly from the 1880s through WWI and independence) ended up splitting into the Socialists and National Democracy (ethnic nationalist, really) factions. However, the group and situation was super fluid until about 1900 or a bit after. So, considering the altered situations in the ATL, there's some real fun room to play around here - the factions could develop differently, you could have people drifting into different camps, OTL enemies become ATL enemies, etc. Add on to this that King of Sweden has said there's actually increased Polish emigration in the Cinqo-verse, you could well have some major figures who stayed in Poland actually emigrate to the United States here instead.
Honestly, with a stronger Polish presense in the United States, I'd say their situation there is even more analogous to the post-Civil War Irish than in OTL. If the Polish-Americans end up coming out of the GAW with more social standing (and, just as importantly, a better economic standing) I'm seeing a LOT of American money being funnelled through Polish nationalist organizations back into Poland itself. And if there is any civil disturbance in Russia post-GAW, there are also going to be a lot of Polish-Americans with military training who would be more than happy to go home and lend a helping hand (which occurred, to an extent in OTL as well - the Polish National Alliance actually tried to organize Polish military units to send to help the allies during WW1. )
Even without an active uprising - a richer, more secure, larger and less divided American Polonia (and I'm guessing that the GAW is more than enough to help heal the rift between the Polish National Alliance and the Polish Roman Catholic Union of America - and the Polish Church War/much of the in-fighting in Polonia began to clear up in OTL at around this point anyway) is going to have major reprecussions in Poland-proper and it's nationalist circles. And that's not even taking into consideration that two of the major partitioning powers are about ready to duke it out in the next few years (I keep focusing on Russia - but Galicia and the German-partitian are equally fascinating situations).
Its kinda a fascinating situation!