Would the US had stayed out of WW2 if Pearl Harbour hadn't been attacked?

In essence, yes you are right. The Democrats held all 3 branches of Government both the House, Senate and Presidency). However the strict facts are Japan declared war on the USA on the same day as Pearl Harbour was attacked, Germany and Italy declared war on the US in support of their ally Japan 4 days after Pearl Harbour.

Roosevelt was sympathetic to the UK (and France) but could not  commit the US forces to open support. In part he had to deal with an isolationist congress and population at large. There were also active elements of the population supporting Hitler. Until Germany declared war on the US (post Pearl Harbour) FDR did a lot to work around the limitations forced on him through the isolationist pressures in congress. US forces started to escort convoys to the end of US territorial waters,military supplies were made available through 'lend / lease'.

Military supplies were sold to the Allied forces (essentially the UK and many |European nations and then to their rump governments in exile. this included sales to Far Eastern colonies of European powers such the the Dutch East Indies.

Despite FDR denouncing Germany and Japan going back to the mid to late 30's (1937on). FDR, like Churchill in the UK recognised the rising threat posed by a resurgent Germany. Fortunately  for FDR he didn't face the active opposition claiming he was a war monger as Churchill did in the 1930's from Labour politicians

You could make an argument that the vested interests of many US companies, such as Ford, GM & IBM all had extensive manufacturing operations in Germany and were worried they would lose such operations.

Politicians spoke out on how they wanted to remain neutral from the "European" war, until such time as Japan attacked Pearl Harbour. But don't presume the US was 'entriely' innocent, the US had been gradually imposing increasing sanctions on Japan though 'economic warfare'.

We started a war with Japan much further back than in the 1940s. Japan didn't want to trade with the US and we opened up with defeating the enemy for no other reason. We made up a few to keep face.

Yes. The USA had a neutral policy toward the WWII. The U.S. also didn't care whether the allies or the axis will win the war. The Manhattan Project was in progress and research on nuclear weapons was being made even before the attack on Pearl Harbor. but the U.S. politicians didn't envision using these weapons. Therefore, from what I understand, the U.S. would have continued to stay out of the war. The attack on Pearl Harbor served as an entry point of U.S. into the war and a call to action for use of nuclear weapons.

I think the US would have had to get involved sooner or later.  Germany was bent on taking over the world basically, and at some point it would have met with opposition.

impossible to answer, since we don't know what would have happened next.

they were building that bomb, so maybe? either that or they wanted to sell it to others. What if pearl harbor was an inside job? modern Japanese people brainwashed to believe it was them. After all, all that remains is photographs, written history and word of mouth. All of these can be fabricated.

It would have taken much longer.  Groups such as the America First committee capitalized on a strong public desire to stay out the war, if possible.  The attack on Pearl Harbor caused opposition to war to evaporate, but only with respect to Japan.  Many people continued to believe that we should let England deal with Germany (which was unrealistic).  FDR hesitated to ask for a declaration of war against Germany.  Then, a few days after Pearl Harbor, the foolish Hitler declared war on the United States, thereby solving Roosevelt's problem.  We declared war on Germany immediately thereafter.

They wanted to, and if Japan had not attacked, the axis probably would have time to win the war. before turning on the US. We were very much isolationists.

However through Oil Embargos with Japan and openly supplying the British and Soviets, it was a fore gone conclusion

The USA would have eventually been dragged in, just as in WW1.  And FDR was much more interested in being involved than had been Wilson.  If not unrestrained U-Boats in the Atlantic, then Japanese pressure in the Pacific.

Germany declared war on the US. That indicates to me, the Axis would have targeted the US eventually. It was a world war.