There were US officers that expected a Japanese air attack on Pearl Harbor, but they were generally low-ranking officers, and you can typically find low-ranking officers who will believe anything. (Gordon Prange, At Dawn We Slept). The best account I've found of exactly what went on is Lee & Clausen's Pearl Harbor: the Final Judgment. There are so many conspiracy theories that it is hard to refute them all in one book, but reading a few good books on the subject will be useful.
One thing that most conspiracy theorists ignore is that the US Army and US Navy sent messages to Pearl Harbor ordering preparation for imminent war ten days before the Japanese attack. It seems to me that, if you warn somebody of an impending attack, there's always the possibility they'll do something about it. Another fallacy that
is sometimes used is the confusion of US officials expecting imminent war (which
they did) with US officials expecting an attack on Pearl Harbor (which they didn't).
The second question is covered thoroughly in Feis' Road to Pearl Harbor (I haven't found a better source yet). In brief, Roosevelt was dragging his heels on sanctions and the like against Japan, in the hope that the US could stay at peace with Japan. (Roosevelt wanted to get into a war with Germany, and in September 1941 ordered the US Navy to fight the war in the Atlantic (Morison, The Battle of the Atlantic). Roosevelt was advised that the materials sent to Japan would delay US rearmament, and allowed them to be shipped anyway.
The tl;dr version of the above:
No high US official expected an attack on Pearl Harbor.
Roosevelt was taking measures to not provoke Japan, in the hopes that he could avoid that war.