So with a kick off in 1917, it would be good to list the status of the relevant nations.
So for GB:
Naval:
-Basically the 1916 OOB but without HMS Erin, HMS Agincourt, and HMS Canada as their sale would have been completed. I think only the first 2 of the R-class as peacetime production and commissioning is a lot slower than during wartime.
-Army:
Half the peacetime army would be in Ireland trying to keep a lid on things. Leaving only 3 divisions for a possible the BEF.
-Politics everyone would be busy with Ireland and the massive fall out of having "English Loyalist" turn violent against the British Army.
-Industry still strong but slowly getting crushed under the combined competition of Germany and USA.
Germany:
Naval:
-Again OTL OOB of 1916 with Bayern and Baden in commissioning at the start of the war, and the other ships in the class still under construction but almost done. The Wittelsbach and Braunschweig class would have been send to the colonies, if the Germans are smart they would have beached them as shore defences around Der-El-Salam, Tsingtao, and Duala making these ports near unassailable.
-Army:
The compromise the SDP wanted was that conscription would be equal for all and no longer have the officers be only Junkers. This was partially done during the 1912 law and would have been completed with a second law in 1914. I also think they would have striped out the cavalry and but them in separate Korps. This would have increased the army by at least 7 Armeekorps and separated out 3 Kavallerie Korps. So 28 Armeekorps + 3 Bayern Armeekorps + 3 Kavallerie Korps + Guardkorps. For an army 4,25 million strong at kick off instead of 3,8 in 1914. Hopefully with lots of additional Rail troops.
-Politics:
As mentioned above the SPD would have just scored big with the reform of the conscription laws. And for 3 years having shown to all and sundry that the D really stands for Deutschland.
However you still got Willy running off at the mouth.
-Economics:
Going strong especially as the Colonies are starting to break even/make a profit. Also as mentioned the Faber process is eliminating the need for Nitrated imports something that would show in the balance of trade.
France:
Navy:
-Having just added the Bretagne class, the French navy now boasts of 7 Dreadnoughts and 6 Semi's. All are still posted in the Mediterranean.
-Army:
Difficult to say, if they had managed to continue the 3 year conscription the same size as 1914. There was no room for further growth, but a new class of heavy artillery is possible.
-Politics:
God only knows during the 3 years there could have been no less then 6 new governments this being the 3rd republic average. The big political issue is the 3 year conscription as mentioned above. Dreyfus would be old news, but I am pretty sure new scandals would have come to light.
-Economics:
Moaning under the cost of the Army, and the colonial area's. The French "wisely" chose some of planets earth least desirable land to colonize.
Russia:
-Navy:
Now strengthened by 4 Gangut's and 3 Imperatritsa Mariya it still sucks the big one.
-Army:
Massive in numbers, but so under equipped that its not even funny any more. The Russian army without GB industry is the prototypical glass canon. We are talking an army/mob without boots or sufficient rifles for all its men, nevermind fancy equipment like ammo or tents.
-Politics:
LETHAL and to the quick
-Economics:
In revolt or on strike, and I am guessing that the French are bitching about repayment of their loans by now.
-Austria-Hungary.
Navy:
Still as OTL but now with 2 or 3 of the Ersatz-Monarch class and a fourth on the slips.
Army:
-Fancy new artillery as mentioned before. But the real strenght is that the second FF take the crown, von Hötzendorf is out on his ass. This also adds 3 years for Diehl to be caught. However under the POD mentioned by OP, I am guessing at least 3/4 of the Honeved has gone with the rebelion. This is offcource balansed by the fact that both the Aurstian and the Comon army would be fully mobilized and in the field.
-Politics:
With a Hungarian rebellion ongoing and a new emperor this would be a mess.
-Economics:
Pre Rebellion booming.
Belgium & Netherlands:
-Army:
Both countries reformed their army and conscription in 1912, so by 1917 they become rather too tough just to walk over. Also the Belgian Forts would have been renovated. This ends any idea of Schleifen after 1916.
I could accept a scenario where Hungary rebels, quickly followed by getting stomped by the Loyalist. However the Serbians thinking the AH is soft quickly enters on the side of the Hungars thinking to cut out all of Croatia. This would make the Austrians go defensive on the Serbian front will continuing to crush the Hungars as they start running out of everything.
It would also beg for an invasion of Hungary by the Romanians (probably with Austrian approval) and of Serbia by Bulgaria, voila a third Balkan War.
So the Serbian intervention would quickly spin out of control. And with the Bulgars approaching Nis the Serbians screams for help, enter Russia. However an entrance by the Russian army in the Balkans, will bring in Germany and the Ottomans.
So now we have two sides:
-Austria, Germany, Ottomans, Bulgarians, and Romanians.
-Russia, Hungary, and Serbia. Quickly followed by France and quite likely Italy.
But a stated because of the defensive strength of the Belgium and Netherlands no invasion/rape of Belgium. So no GB at first, and most likely not at all as the Naval race has puttered out, and with the QE and R classes coming online a clear win for GB.
It becomes quite hard to point with alarm at a navy you out number 2 to 1. Also the entire British Foreign Office would be cackling with glee, at the thought of the continental powers mutually destroying eachother.