Follow-up question: did the Roosevelt administration have any plans for Japan had they not bombed Pearl Harbor? That is, even if the US was going to declare war on Germany, was there any plan to do anything about Japan?

I'd love to see a proper historian answer this, but you've piqued my curiosity enough that I did a bit of research.

They certainly had quite a few war plans already drawn up - in 1939 they drew up five "Rainbow Plans" that dealt specifically with how they would go to war against the Axis powers. wiki link.

From what I can see after a bit of wiki walking and reading over some of the citations, it looks like Roosevelt and the military staff expected Japan to attack the USA for several weeks before Pearl Harbor. The Navy apparently sent out a memo in late November warning that the Japanese were probably about to attack, although they didn't have any indication the attack would be on Pearl Harbor. The memo

As a bit of conjecture, it seems like around the summer / fall of 1941 the president and navy staff were expecting Japan to attack US territory, and may have planned to use that to get the war started.

According to this MIT Paper looking at American opinion in 1939-1941, it seems that popular support for supporting England in the war didn't even cross 50% until Fall of 1940. Seeing as how Congress always lags behind popular opinion, I wouldn't be surprised if a voting cycle would have needed to happen before the sitting congress would have voted in favor of a war. (check page 19 of that paper for an easy to read graph.)