Was the impending Pearl Harbor attack known in advance?

One thing you don't understand, is that I believe that in the event of what you were talking about, a project for a bomber like the B-36 Peacemaker would have been given a very high priority. The fact that it was even on the drawing board was a preparation for circumstances which didn't eventuate. I am suggesting that if circumstances demanded it, its priority would have increased up the list. The B-36 Peacemaker was started in 1941 and flew in 1946. I am saying that this time could have been reduced if there had been a need for the aircraft. The B-29 first flew in 1942 and was in squadron operation in 1943. Therefore, there is no reason to suggest that if necessary the B-36 Peacemaker could not have been produced in a shorter period of time than it was in this reality if there was a need for it. The B-29 was considered a very complex aircraft when it was first produced. And yet, two years from first flight to squadron service. The B-36 Peacemaker took 3 ending up in squadron service in 1949. This is a well-reasoned argument on my part as the USAF considered its projects on the basis of what it needed at the time. At the time, the US had the power to seize those islands at great cost due to their air power and naval power. Therefore the suggestion is that after Coral Sea and Midway the project for the B-36 Peacemaker perhaps didn't seem as important for Consolidated and thus was perhaps partially shelved.

Comparing the B-36 to the B-29 programs doesn't make sense. A lot of the B-29 program used parts and lessons from the B-17 program.

The design for the B-36 was preliminarily submitted on May 3, 1941. Consolidated was too busy building B-24s and B-32 to give more priority to the B-36.

Boeing submitted the prototype design for the B-29 to the Army in 1939 (http://www.boeing.com/history/boeing/b29.html). It was three years before the first one flew. And even after that, there was a lot of testing and rework to do before it was operational.

Besides Healzdevo compare the B-29 to the B-36 please. Jet engines were still in there infancy in 1945 and you are thinking that the B-36 could have been ready to fly as early as 1941. Come on now!!!

You have to think a bit realistic now...

The B-36 was way more complex than a B-29.

Even if the US would of lost Coral Sea, Midway and even been repelled at Normandy, the B-36 would not of been ready for flight by 1945, it's that simple. Even given the people, material and priority technology doesn't materialize based on numbers and as stated the B-36 was a very complex aircraft.

And I'm not even talking about the addition of the jet engines....

The P&W 4360 engine slated for the bomber was having just as difficult of a time getting its bugs worked out as the Wright 3350.

Even if the airframe was completed by 1945, it wasnt going anywhere untill the engines were working.

Thus no B36 flight untill when it actually happened, in 1947.