I think this goes without saying, WWI, IF Germany doesn't provoke the US entering the war.
The war would have gone just as we expected up to the opening of Ludendorff's spring offensives.
No, No. Definitely not. Now what you are trying to do is ok for analysis part, but there are HUGE butterflies to deal with, including:
1) Without the hope provided by the USA entering the war, the Whites may make peace. If they don't, it is unlikely that Lenin will follow the same negotiating strategy of trying to wait it out. Most likely the peace treaty is signed months earlier, and I would not rule out a date as early May 1917 for Russia, depending on the German terms. If I had to pick a date, I would be on November 1917.
2) Without the USA entering the war, the blockade on German is not as tight. The USA was diplomatically fighting against it, the USA ships helped enforce it, and the UK is running low on money for things like fuel for their ships, see below.
3) The UK runs out of things to secure loans with in the USA, so about a 20-25% reduction in UK imports which means shortages. We could write a dozen TL on how this plays out, but some likely side effects are
A) Lower morale in UK and France because of a lot less food and consumer goods. A lot depend on exactly how the handle the rationing, and the exact dynamics of the U-boat war using cruiser rules or whatever your TL would have.
B) A lot lower casualties for the Germans. Artillery does 75% of the killing, and with 25% fewer shells, it is around 18% few KIA, WIA for Germany.
C) With the shells and other war supplies, the Entente will cancel offensives. Again, we can write of few TL on how this unfolds, but I would bet on cancelling the attack into the Holy Land and Mesopotamia.
D) Then there are lot of secondary effects that one has to look at.
4) Will the French units even attack in 1917 without hope of the USA saving France? You have to determine how the French mutiny ends. It is likely to be in a way that is even worse for France than OTL.
Without US forces now bolstering the flagging French and British troops German forces are able to better hammer home their own advantage. Germany would have just injected an addition 100 Divisions (I think those were the numbers) into the Western Front with the 150 Divisions they already had on the Western Front). The German Army just received a massive amount of reinforcements while Britain and France can't get reinforcements at all, this the final hammer comes down. By this point I honestly believe the French would have collapsed under the pressure and surrendered. Its likely Britain could have escaped the same fate and gotten a negotiated settlement out of Germany keeping their Empire and everything else intact. France likely would have had to give up the last piece of Alsace-Lorraine they were holding onto, possibly a few of their African colonies. Belgium would have stayed occupied and likely ended up annexed by Germany and its African colonies also annexed by Germany.
Beyond that, I don't want to speculate in fear of having people swarm me
Yes, Germany has many extra units, but 100 is too many. Even if all the units from the east are freed up, and they will not be, where does the ammo come for the 100 divisions to use come from. Also, many of these units are made up of older men, who are poorly suited to attacking. Fifty year old men don't walk as far as 20 year old men each day.
And the French and UK can get reinforcement to France. They can stop attacking into the Holy land, probably corp plus. They can pull out of Greece. They can pull units out of East Africa. The UK keep a ridiculous number of units in England, they can pull several hundred thousand out of the British Isles, not there is a risk of revolt, but they have options. Now no where near as many units as the Germans, but they can get units.
Now to what I agree with you. If you get to 1918 in a similar situation like ours, with extra units for Germany, and no USA savior, the Germans would launch a big offensive, and it would work better than OTL. I think France is more likely to negotiate than surrender, but I can't rule out a collapse. Germany is in horrible shape. A-H may be near civil war, and Germany would want a peace deal to preserve the gains in the east. The UK would get a negotiated settlement or could even chose to fight on if France surrenders.
How the settlement is handled is often debated on this forum, but I don't see Belgium being annexed. The Germans will either give the British a face saving solution or actually allow a free Belgium. The Return of the German African Colonies and the Belgium Congo in exchange for an independent, neutral Belgians will look good to the Germans. France will likely try to trade either conquered German colonies or French Colonies for the return of French lands. The Kaiser will be tempted to keep the French industrial heartland, but it is unclear if he would actually do it.