>>Was Pearl Harbor a FF to get the US into WWII?
In brief, yes. My high school history book had a photo of the letter FDR sent to Japan's emperor which issued an ultimatum, either Japan attacks the USA or USA will attack Japan. It also specified that the entire Pacific fleet would be in Pearl Harbor on December 7th.
The fact that FDR ordered the entire Pacific fleet to hang around Pearl Harbor around that date is widely known and reported. The letter is less widely known, but can still be found online without much effort.
Summing up, YES, Pearl Harbor was an arranged FF.