It's funny how in so many Ottoman wanks have in common the non-Muslim territories swamped with Muslim settlers (and usually the Christians emigrating). Rather at variance at the general forum's view of tolerance and support of multi-ethnic countries...
This would require an amazing victory by the Ottomans, considering that they're fighting Greece, Serbia and Montenegro at the same time. I don't see how your POD would improve their strength that much.
As for the assumption that WWI would break out in exactly the same way, this is in fact very unlikely. In any case the Ottomans have more to gain from a war with Russia and Britain than one with Austria-Hungary.
So while fighting the Central Powers, the Ottomans start another war against a neutral country as well, which is an ally of Russia? I can't really see the Entente liking this very much
Crimea was mostly Russian and Ukrainian. I don't really see the Ottomans keeping it against any but the weakest Russia that would be around after a civil war (and a civil war breaking out over a Depression seems very unlikely).
This is because all of the Great powers
signed a treaty that nominally returned Eastern Rumelia to Bulgaria while de-facto keeping united with Bulgaria. And of course Eastern Rumelia itself was an (autonomous) Christian region, though I don't think this is why the Great Powers prevented its return to the Ottoman Empire. More than likely it remaining Bulgarian was aligned with their interests (Britain preventing Bulgaria from completely falling into the Russian orbit and Russia keeping their influence in Bulgaria).
First, the Ottoman Empire never agreed to giving autonomy to anyone without a fight. For example, in 1876 with threatened a war with Russia and without British support, they still refused giving autonomy to Bulgaria. Second, autonomy almost inevitably lead to independence anyway and even when the minorities demanded autonomy, they usually only saw it as a stepping stone to fully independence.
Where do you get these figures from? The number of the Christians are from the Ottoman census of 1914 and are widely considered to be a significant underestimate. On the other hand, according to the same census there were 15 million Muslims altogether (with a total population of 18.5 million). Where do the other 10 million come from?
Again, I find it fascinating how even the defenders of the Ottoman Empire seem to think that they would never really prosper with a large Christian minority.
Considering what happened
before and
after the period you mention, probably wouldn't have been a bad idea. In reality, Russia never spent very significant resources on supporting the Armenians (let alone the Kurds, which would quite counterproductive if it had happened) and generally had relatively correct relations with the Ottomans between 1878 and 1914.