The fact that among those alternate histories those which mention russia all treat it as either a respectable rival or a potential reliable ally is mind-boggling. Something very strange is going to happen somewhere down this timeline, I'm thinking.
Let's just say nobody's gonna be singing "back in the USSR" which means that perceptions of Russia in the latter half of the 20th century are going to be very, very different. Indeed, there's a strange sense of political belonging to the United States and Russia despite
vastly different political systems that was commented on by many in the 19th century. Absent the Soviet Colossus and, to be clear, WWII and WWI as we know it, there's more these two nations might agree on versus disagree on.
It's extremely hard to imagine that the UK, France, and the Confederacy could actually defeat Germany, Russia, and the United States in a total war. If OTL took four years to defeat Germany alone, what about defeating three highly militarized Powers whose industrial power combined overcomes the Entente at least five or six times? Even then, the country is so big they can't simply enforce any harsh peace treaty/occupation.
The Achilles Heel of all three nations is commerce. For Germany in WWI it was the simply
brutal British blockade that wore them down and helped rot the German economy from the inside out. For Russia, it was a combination of Britain and France locking the Baltic and Black Sea (and to an extent the Pacific) down so that Russia could not take advantage of international trade and, more devastatingly, the abrupt loss of access to loans and foreign banking provided by Britain and France. Ditto for the US in the
Wrapped in Flames scenario where a shut down commerce and lack of access to foreign loans and a suddenly
massively dislocated internal market ground the economy to the nub.
But could Britain and France and other hangers on inflict the same to a combination of Russia and America, let alone the third wildcard of Germany*? No.
Some of that calculation is based on OTL's lead up to WWI and all sides adopting similar measures. However, it does stand to reason that such alliances wouldn't work out. For the most part.
I think calling them "these United States" could probably refer to a civil war that transpired or a complete reformulation of the government structure.
Whose to say
Though I want to note that prior to the Civil War OTL it was still common to think of the United States as a collection of states bound up in one nation, while everyone was American they still had identities that coupled with their states, and the state governments felt they had powers and priviledges that were outside the Federal government's purview (a problem that absent the Federal Government being willing to disabuse the states of that notion means they can do some rather gross stuff). In the aftermath if a successful rebellion by a collection of states to such an end, its an open question how the US grapples with that in the aftermath.
Hard to imagine that the USA would make the same mistake twice and not have a gigantic army/navy built during the pre-war period to fight against its enemies. Even harder to imagine the UK/France/Confederates could actually defeat it in the field. Or better yet, what about the new revanchist government considering the Confederacy to still be part of the USA as a new policy, hence the term "these United States"? It wouldn't include just the nation itself, but also the "rebel states."
What I do think it happens is an extremely multipolar world. The USA can't project its power as well as OTL, so you have this world filled with small spheres of influence and shifting rivalries. The UK probably already made peace with the USA a long time ago and now France is their main worry.
On all this, I like the way you're thinking!
They got warm water ports.
All jokes aside, no previous baggage with them, it could be easy to get to if you invest in Siberia, and not a lot of viable alternatives.
Well it was mentioned that they would up their investment in the Pacific and having an puppet nation near a valuable trade route where they can also dock their ships would be very useful.
Ah the Pacific, so many opportunities the Russians would like, and ones the British would go into absolute conniptions if they saw the Russians pursuing them. Interesting times, interesting times...