Or were they expecting America to attack them in response should they do that, and would have preferred to start the war on their own terms, so to speak?

This is basically it.

The problem for the Japanese war planners of the day was the Philippines. The Philippines was in American hands, and Japanese ships attempting to reach Dutch East Indies or British Malaya and Singapore would have to sail past the Philippines to en route. The Philippine Islands are in a very good strategic position to block Japanese expansion to their south.

The Japanese saw war with America as inevitable. America had made quite the stink about Japanese actions in China and Indochina, eventually going so far as embargoing several goods crucial to the maintenance of the Japanese Empire and the war effort in China. Japanese leaders wanted to attack British and Dutch holdings in order to acquire their resources, but they also thought that America would enter into war with them even if Japan only went to war with Britain and the Netherlands. If America went to war with Japan on America's terms, the Philippines would serve as the perfect base of operations for the US Pacific Fleet.

As a result, Japanese planners decided that it was best to strike the US Pacific Fleet and take the Philippines before the US could effectively react. The IJN would then slowly wear down the US Pacific Fleet as it moved across the Pacific (with submarines, aircraft, and night battles), before engaging it in a decisive battle and defeating it. With the US Navy defeated, Japan would be able to secure terms that would have allowed them to keep their new gains.

That plan obviously failed on multiple levels during the war - the IJN botched several of their encounters with the USN (most notable at Midway), and ultimately speaking the Japanese severely underestimated the US's will to fight - but nonetheless there was some logic to it at the time. If you think that war with another power is inevitable, you might as well initiate the war yourself in order to try to gain the upper hand.

Whether the US actually would have gone to war with Japan had Japan only attacked the British and Dutch is another question, and one that I can't quite answer. I'm not that well-versed in US politics of the time.

An important thing to understand is that we now, with the benefit of hindsight and perfect information on all side's strength and weaknesses, know that America's entry on the Allied side was the single most important thing that made Allied victory not only possible, but inevitable.

The Axis did not have this perspective. Now I'm not versed on the exact knowledge and internal politics of the Axis powers. But afaik what they would've in general known was that America was definitely on the Allied side (America was covertly doing everything it could to aid the Allies), but for whatever reason was not willing to declare war as of yet.

Now, if you could go back you'd tell the Axis to do everything in their power to prevent an American entry into the war. But at the time, you'd have this economically powerful country, almost blatantly doing everything it can to provide aid to the countries you're at war with. Why shouldn't you just go ahead and make it official that you're at war?

Also, and this may add some perspective. It is my recent understanding that in WW1 Germany was doing everything it could to keep England out of the war. But they just got outplayed by the English pro-war politicians and Britain entered the war anyway. So in that context, if I was alive at the time, I wouldn't have that much confidence that Roosevelt couldn't get America to enter the war anyway either.