I basically predicted it in a worse case scenario in the last part, so why not
First off, hard line alliances
Allies(i.e. The west): Britain probably be the leader of this alliance, with America cleaning up its act, and Europe needing a rallying point.
So, most of Europe, if not all, America (explained later), some of africa, maybe India, though not in a very active sense, plus the commonwealth(Canada, Australia, the like), Japan, Taiwan
Axis(i.e. Russia+)
Russia, or course, some of the middle east, maybe some of South America
The neutrals(or, third party)
Most of africa, possibly India, especially if it does then into a third alliance, south/central america, Oceana

China is the real wild card here, in all honesty. When the war breaks out America is going one of two ways
Either A, the Trump scenario, with no or half hearted support to the allies, leading to a civil war, effectively taking America out of the war,
Or B, a strong, though not as dignified America eager to prove itself as a true power once more

Now, when Russia does invade, China will either end the war, or make it last
If China perceives America as weak, it will push into Japan, Taiwan, and into Oceana, along with (possibly) india. Russia will welcome Chinese support, and the two will most likely have all of Asia under their thumb.
In this case, Australia becomes exceedingly important, as a staging base for missions going into China, and a bastion form oceana and the commonwealth to rally around. Either way, America will be stretched thin, and both parties will push their advantage, possibly invading large swaths of Europe and the ME.

So, the real question will be how well Europe fights. Will they give it their all, or be crushed one by one, instead of showing a unified front. Canada, or course, will be a major player, even more so if America is out of the war. They will be tasked with both providing support to Oceana and Europe and making sure Russia doesn't make inroads in the Americas. Now, the real important things come into play. How long does Japan hold? How many men can SK and the Allies get out before China and NK crush the peninsula? They have a decent chance at holding for as long as they can get supplies, but China will blockade the southern country, and after that it's a game of attrition.

Plus, Europe and the Allies will feel the economic pressure of lacking China as a trading partner, and be forced to employ more people, while at the same time drafting more service members. It will cause labor prices to skyrocket, forcing the Allies into a depression, which will further increase the confidence of the Axis.

And here Africa becomes important. If the Allies turn to the continent for labor and men, they can gain a definite edge over Russia, even when the Chinese machine pumping into its war effort. Africa will be uplifted, which may lead to a dominant world power forming there, possibly S. Africa. With that boost, if they take it, the Allies will be able to push Russia and China out of Europe, while sustaining heavy losses, or course.

But the general Winter comes into effect, in which case, the Allies turn their attention towards liberating SK, Taiwan, possibly India, if it has been conquered, and Japan. If India has been conquered, there will be hardline resistance groups there, people the Allies can use to help fight. But they will also have to donate e with the fish of conscripts coming from the country. If they liberate India first, they can actually ride that wave, and drown China in men form both Africa and India.
NK just be dealt with quickly as to avoid nuclear conflict, probably with a surprise invasion and capture of the capitol within hours, assisted by airborne forces, including paratroopers. This will allow the Allies to open two fronts against China, splitting its forces, and give it time to liberate Japan and whatever bits of Oceana China conquered. Once you have pushed China inward, you wait. Starve them out, let their resources drain.
But hit Russia in the spring, make for Moscow, and the countries oil fields, along with an invasion from Alaska, headed by Alaskan troops used to the biting cold of the North along with Canadians.
Once you have control of Easter and western Russia, have more of less encircled China, you wait. Starve them, they will surrender. Keep up the pressure with bombing raids, sedatives and the like.
Of course, I haven't addressed two situations
If this goes nuclear, everyone does
If China joins the allies, Russia is screwed
That's all folks.