I'm a big believer in not fighting the hypothetical, but there is no historically plausible account leading to the destruction of the Atlantic fleet. At that point, we aren't discussing facts relevant to whether FDR knew of the Pearl Harbor attack ahead of time.

The hypothetical of Pearl Harbor as the most resounding success it could possibly be (US Pacific fleet reduced to irrelevance) and Germany winning the Battle of Moscow strongly enough that it has leverage to force the UK out of the war is reasonable for discussing FDR's decision process. That's all he could reasonably have thought he was risking by allowing Pearl Harbor. As I stated elsewhere, I think FDR gets his political goals with Japan firing the first shot - there's no need for him to court a military disaster.