(1) Would there have been a European union long before It did in the present timeline and doing so provide a countermeasure against America as our economy became better
(2) Would America become industrialized as quickly as it did in response to WWII and not have had to help Europe rebuild if WWII had never happened?
(3) Would the Ottoman Empire had fallen in the way it did and allowed the France and Britten to carve up the middle East in their own fashion?
(4) Would WWII ever have happened and with the atrocities of the Nazis?
(5) Would the UN had have been created and in being not doing so, Would Palestine have been carved up to create the state of Israel?
(6) Would America have become the superpower it is now if Europe had not devastated itself in WWII and would nuclear power have seen the light of day in a devastating bomb?
(7) Would a united Europe, not engaged in their own war and an America set back and watched Japanese aggression in China and if not would China have become communist?
(8) Would Russia have grown into a super power if they hadn't have had to fight Germany during WWII and not have had Eastern Europe as the spoils of war
We like to think that Nazism was the result of their defeat in WWI. Modern historians think that things would probably have played out in a similar fashion. Authoritarian and anti-democratic ideals were found all over the west. Social-Darwinism was all the rage. The Catalyst for German Nazism was the attempted communist coup 1918, which was almost successful. Well.. both Nazism and Communism was the zeitgeist, no matter what either side would have done.
1) The European Union was a direct result of WW2. So probably not.
2) Wars are expensive. As a general rule, an economy expands faster the fewer wars a country it is in. I don't think USA's economy sped up as a response to WW2. Their GNP went up. But GNP isn't the same thing as an economy. It's just a metric we use for simplicity. Because measuring the real economy is hard.
3) Nope. It would not. The Ottoman empire might have reformed and come out quite healthy.
4) Probably. It was the Zeitgeist all over the west. We've just gotten a collective amnesia regarding the Nazi type ideas in the non-German part of Europe. Churchill himself was a raging white supremacist. He was guilty of much the same kinds of things when he was a soldier in the colonies. He had very much the same values regarding race as Hitler.
5) Nope. The UN was created as a direct result of WW2 and the failure of the League of Nations. The League of Nations would still have failed. So perhaps something similar.
6) USA was also in WW2. So the answer is, yes, they would. USA became as rich as they did because in the first half of the 20'th century USA was the Saudi Arabia of the world. USA reinvested that money which created an enormous boost to the economy USA is still enjoying.
7) Remember that China was free money for Europe. It was their little plaything they were bleeding dry. Which gives them a incentive to defend China from Japan. And since Europe was rabidly racist, they were unlikely to sit idly by while Japan created an empire. If it wasn't for German aggression in WW2 Japan would have been stopped in their tracks by Europe. Not many people remember this. But before WW2 (and WWI) Germany was allied to China/Guomindang. As was USA. Because both Germany and USA were allied in their quest to stop Western exploitation of China. While Japan just wanted to be part of the France/England and Russia party.
8) What caused the Russian Tsar to fall, and communism to happen, was Nikolaj II's obsession with Russian getting Constantinople. He bled Russia dry to win that victory. That would have played out the same if Germany won the war. If Nazism would have come anyway, Germany would probably have attacked Russia, just like before. Because no matter if Hitler was in power or not German industry still needed oil. So the Baku oil fields would always be a tempting target. Germany being forced to sail past enemy France and England for oil was like having Germany's balls in a vice.
The big unknown here is Austria-Hungary. Europe's biggest empire and most populace European power. If they would have won that would have changed German politics a lot. Since Germany would have been dominated by Austria-Hungary. Austria-Hungary would still control Croatia and parts of northern Italy, so would have ports in the Mediterranean. That would have changed much. Instead it was turned into a bunch of ineffectual quarrelling kingdoms. Who knows what they would have done?