Obviously she is having us do her homework, but it is an interesting subject.
United States, Britain, and Japan would have high living standards comparable to today?
Yes. But their debt ratios would be better off, because instead of WWII, the global crisis would be pushed back to 1966, and take the form of US support for other British colonies who want to repatriate their constitutions and chart their own course. As a result of the global conflagaration, which lasts until 1971, the baby boom happens a generation later. The early 1990's become the equivalent of the late 1960's, and a generation of hoppies (instead of the familiar hippies in this universe) choose extasy instead of acid and weed as a way to open their minds - their movement involves a lot of hair brushing and touching things with their finger tips instead of the 'cerebral' nonsense of our own hippies. World population works out to be about the same, driving similar economics, but India remains part of the British Empire, as the limeys brand Ghandi as a 'peace terrorist', and put down potential rebellion without provoking global indignation but slaughtering cows every time there is trouble. Clever toothless islanders.
Would Russia be higher than us?
Given all the extasy going around in the west, I would have to say no. In fact, it is very hard to get your hands on anything in Russia. The Czar, Emperor Vladimir Putin, runs the place like he owns it, arbitrarily arresting people for criticizing him. Russians themselves accept things as they are, roundly agreeing that they need a 'strongman' like him as the leader. He makes forrays into capitalism, and lets a few businessmen make a fortune and grow in power until he changes his mind, and strips them of everything they have and puts them in jail on trumped up charges. He goes hunting, and has a national magazine photographer take shirtless sexy photos of him to attract courtesans from Chiang-Kai-Shek III court to his lair.
Would Europe and Australia (and New Zealand) still have high standards of living?
Europe would not - internecine violence and old money make poor bedfellows. The EU does not rise, and with Germany rendered an agrarian wasteland, France, the UK, Italy, and Spain vie for dominance. Other powers are content to let the Europeans continue to divide and rule themselves.
Australia still has high standards of living, but is under pressure from Greater China, which, following a more agressive interpretation of the '3 island-chain' strategy, has outright conquered Korea, Vietnam, as well as key islands from Malaysia and Indonesia, where they are able to leverage a large Chinese ethnic population. Australia therefore spends an inordinate amount of its GDP on its navy, and works with the US to contain Chinese imperial ambitions. New Zealand, as always, is given only a nodding acknowledgment of being on the same planet.
And finally, would technology progress to the point we have today??
No. Without the pressure of a cataclysmic war in Europe, and the extermination of the Jewish population, a young Albert Einstein does not emigrate to the US in 1933, and instead follows in his father's footsteps, and becomes an accomplished electrical engineer. There would be no Mahattan Project anyway, as there is no WWII, and no V2 (Braun goes into rockets, but without the funding of a major war, instead builds a model rocket empire and fireworks factory), so the Mercury, Gemini, and Apollo programs never take place, leaving us a world without Teflon.
One last thing - Kennedy doesn't get shot, but nor does he get elected due to a simple prejudice. In this universe, 'chowda' is a colloquial term for blowjob. When he invites his opponent, Nixon, to a clam chowder lunch, Nixon, every the Machiavellian, twist the invitation into a public outrage, and activates the Catholic vote outside the Boston area. He win the election, and America prospers. The Dead Kennedys go with and alternate name, the Mellow Muffins, and fail to attract the scorn of Tipper Gore.