So, I have a couple of events that I was wondering about how to go about butterflying.
1) France and Germany sign a peace treaty in 1917 ending the war on the Western Front in a status quo ante bellum.
2) No Russian revolution until after the war.
3) Austro-Italian Front role reversal (Austria gets pushed back until the end)
4) Bulgaria joins the war in 1914, leading to a quicker Serbian defeat.
5) Romania remains neutral or joins the Central Powers.
Any chances? How would I go about this?
I'll look at 1) at the end, since it seems to be reliant on the other aspects going other ways.
2) If you mean a Russian Revolution of any kind, this is possible, given dissatisfaction with Nicholas' ineffectual military exploits. If you mean a Bolshevik Revolution, this is virtually impossible. They were able to take over precisely because they marketed themselves as the anti-war revolutionaries, which gained credence after the Provisional Government (under pressure from the Entente) refused to end the war with Germany.
3) Could theoretically happen with a disintegration of the Balkan front, although unlikely. Protecting the approaches to Vienna would be a greater priority than the Southern Balkans, IMHO.
4) Too early for Bulgarian entry. Tsar Ferdinand had courted both alliances. If the Bulgarians join too early, it risks putting the Turks into the Entente camp. It took a while for the Germans to convince the Turks to promise to give Adrianople to the Bulgarians after victory (I imagine they would backstab the Bulgarians in the end), without which I doubt they would join the CP.
5) Romania remaining neutral or joining the Central Powers is relatively easy. Neutrality can be assured without the Brusilov Offensive. They could join the CP if the Russians looked like they were on their last legs (to secure Bessarabia). But there is the complicating factor of Bulgarian claims to Southern Dobrudja.
1) Really depends so much on the course of alternate WWI that it can't be answered properly, IMHO :/