Trying to keep to the purely warbirds related portion...

an an air carrier group, even today, has limited assets. Yamamoto tried to select targets carefully for maximum effect with those limited assets. Even though the IJN initiated a carrier strike, the mindset then was still battleship dominant, so battleships were the target. The fact that civilians were not targeted was a simple cost effectiveness calculation. That said, the targeting showed that Japanese thinking was still very tactical and not strategic. As our own review of the attack determined (1942) the IJN misprioritized the targets. What would have Had a much more serious impact would have been targeting the docks, repair facilities and especially the fuel storage facilities. The saying goes that tactics wins battles, logistics wins wars.

The Hague Convention of 1907 (After the Port Arthur Raid and the Japanese victory) was clear that notification had to be given before the start of actual hostilities. The Japanese tried to deliver the declaration a few minutes before the attack commenced, but were delayed in D.C. So they were trying to meet the letter of the law while avoiding its intent and wound up unsuccessful.

Clausewitz wrote in the early 1800's that strategic surprise was difficult or impossible against a reasonably intelligent opponent. There are too many signs that a war, or even a major military operation is about to happen. These cannot all be hidden. The element of surprise then, is left to the specific timing and place of the attack. Such was true in 1941. Our military and civilian leadership knew war was coming with Japan. Hence the "two Navy" appropriations act of 1940. That air power would be decisive was also no surprise. All of the airplanes we won we won the war with were in design or on order before Pearl Harbor. Up to and including designs studies for the B-36. As the time got closer, we kind of figured that war may even come before the end of 1941. But we did not know exactly when and our best guess would be that the attack would fall on the Philippines. Of course, when the Philippines were hit, they were still unprepared, even though they knew the blow was coming and that it would come first by air attack.