US does not enter the war on the side of the Entente
For that to happen you´d need to deal with 3 things:
- the Wilson administration which wanted to enter the war
- the German government which in its stupidity played into the hands of the Wilson administration (Zimmermann telegram, unrestricted submarine warfare)
- and maybe US banks which by that time have loaned a lot of money to the Entente powers. And facing the possibility that the losing side (especially Russia, maybe France and Italy?) might not be able to repay the loans.
German victory is late and not thorough; France is overrun either in 1918 or next year but Germany itself nearly collapses
In that case a negotiated peace of exhaustion (your point 3) seems plausible. However in that case I also see considerable pressure in Germany to move closer to a constitutional monarchy. Social Democrats, Catholic Center party (Zentrum) and the progressive Liberals after all do have a clear majority in the German parliament (Reichstag).
Millions of death and crippled soldiers aren´t exactly a recommendation for the old system.
It´s also possible that Emperor Wilhelm II might be forced to abdicate in favor of his son. His battlefield tourism (safely in the rear) and his "leadership" during the war made him somewhat unpopular...
The peace treaty is much less harsh, as Britain is still able to enforce some of its ideas; as Britain continues to rule the seas Germany makes no massive colonial gains
As I said above, plausible if this is a negotiated peace of exhaustion.
No great German gains in the West, no crippling reparations and no massive colonial gains. The treaty of Brest-Litovsk probably won´t be part of that peace treaty.
On the territory awarded to Germany by the treaty of Brest-Litovsk a chain of buffer states are formed: the Baltic States, Bielorussia and Ukraine; Poland becomes incorporated into Germany
You forgot Finland.

The rest is plausible with the exception of Poland. Won´t be incorporated into Germany. Don´t think Germany wants even more Poles inside Germany. It´s much more likely that we see "Congress Poland" (maybe with some parts pf Bielorussia and Austrian Galicia added) as an additional buffer state.
And all of them will probably be drawn into the German economic sphere.
Russia becomes communist, just as in OTL
Well, possibly...(to channel Blackadder

)
Of course with Germany not defeated (no Versailles treaty) I would expect more German support (equipment and volunteers) to the White Russians?
Once the Great War ends I just can´t see Germany not involved. They´ll switch sides immediately.
Patriotic pragmatic German Social Democrats are one thing, atheist revolutionary Czar murdering Russian Communists are another.
Austro-Hungary disintegrates, with Greater Hungary, the Czech lands, Croatia and Austria becoming independent
Uh oh, a powder keg.
And no, if Austria-Hungary disintegrates, (German-) Austria will join Germany. The question is, in what borders? And what happens with minorities?
- How do you define Czech lands? German Austrian majority in the Sudetenland for example. German Austrian minorities in Czech cities. With an undefeated Germany you´ll likely see a smaller Czech state.
- Greater Hungary included - if I remember correctly - Croatia? And Slovakia too? So how does Croatia become independent?
A combination of feeling betrayed by the Peace Accords and the Great Depression brings to power sth like the Nazi Party in Germany in a more or less analogous way to OTL Italy
But Germany didn´t lose the war?
And German speaking Austria is now part of Germany. The "Reich" is larger.
No Versailles treaty and no reparations (except maybe to Belgium?).
One main reason for the Great Depression in Germany were the reparations. Getting US loans which were then transferred to the Entente countries as reparations. Who then used the money to repay their US war loans. Nice money circle for the USA.

And when the Great Depression started in OTL the US banks wanted their German loans back. And Germany couldn´t deliver.
Without Versailles there´s much less need for US loans to Germany.
Likewise without Versailles the German industry doesn´t lose its patents. Before WW1 the German chemical industry had an almost monopoly on dyes for example. So exports in the 1920s will be higher.
Not to mention that the new buffer states will be export markets for Germany.
WW2 goes on in a roughly parallel way to OTL with Bielorussia and Ukraine playing the part of Poland
Why?
Germany doesn´t has any (Versailles) territory claims against Bielorussia and Ukraine. Quite likely both of them are in the German economic (influence) zone. So why attack them?
And just to mention it.
The German generals in OTL weren´t that convinced of Hitler´s plans. There were quite a few assassination and coup plans. In your TL the generals still have a "higher" authority, the Emperor. Which means that in your TL the officers never swore an oath to obey a Nazi "Fuehrer". They´re still loyal to the Emperor, making it much more likely that more of them would support a coup if they felt that the country was in danger.
(In the - in my opinion - unlikely case that a Nazi like party would get a majority in your TL.)
At the end Germany is defeated and the maps are redrawn sth like OTL
Given my comments above I just don´t see any reason why your TL Germany should start WW2?
Likewise your TL Germany is unlikely to produce anything like our TL holocaust. Just like our TL fascist Italy - which you used ("i
n a more or less analogous way to OTL Italy") didn´t produce something like that.
Seems to me that if you somehow get your (Turtledove) result you´ll get a resentful post-WW2 Germany analogous to our TL post-WW1 Germany?
