The Current World Map Without the World Wars

In regards to Austria-Hungary, I agree that it is going to be a challenge to create a viable multi-national federation. Still, it wouldn't be completely impossible. Also, interestingly enough, if this federation--with a Hapsburg as a constitutional monarch--is going to be a success, then I wonder if, say, Serbia, Romania, and Poland (if/after it will acquire its independence from Russia) would try joining this federation. After all, this would be a great way for them to reunite with their ethnic kinsmen across the border.

In regards to Russia, I could see it eventually losing Poland and perhaps Finland since these areas had strong national identities. Indeed, the Poles especially were a huge pain in the ass for Russia--rebelling against them in the 1830s and again in the 1860s. Indeed, I doubt that a democratic Russia would have been particularly eager to hold on to Poland (though it would probably insist--perhaps as a precondition to agreeing to Polish independence--on Russian troops having free passage through Poland in the event of a future Russo-German war so that Russia will be able to continue honoring its alliance with France). However, I do think that Russia would have been able to keep control of all of its other territories. Without Galicia, Ukrainian nationalism would have been less of a potent force in the rest of Ukraine. Meanwhile, Belarusian nationalism was almost nonexistent during this time and, as for Central Asia, Russia would probably be willing and able to use force to maintain control of Central Asia if it came to that--though Russia would also benefit from more extensive Russian colonization of Central Asia considering that it would make Central Asia easier to hold on to.

As for the Ottoman Empire, I could see them trying to develop a common Islamic identity in an attempt to suppress Arab nationalism in their territories. As for whether or not it would work, I'm not sure. However, it is worth noting that the Ottomans would have probably been extremely unwilling to let their Arab-majority territories secede due to the fact that some of these territories--such as Iraq--have a lot of oil. If anything, I could actually see the Ottomans eventually conquering Saudi Arabia in this scenario. Of course, if the Ottomans still attempt to engage in either ethnic cleansing or genocide against the Armenians, I could certainly see Russia invading them and forcibly taking the Six Armenian Vilayets along with the city of Trebizond.

I do think that the German Empire is going to be able to keep its 1914 borders to the present-day in this scenario--though it might perhaps eventually be generous enough to agree to a plebiscite in Posen Province given how annoying the Poles there were from the perspective of the Germans.

As for the colonial empires, I agree that the European countries would probably be unable to permanently hold on to most of their colonies. However, would there be any exceptions to this rule, and if so, which ones?