Well in Rowley's memo to Mueller she said the agents had contacted the CIA counter terrorist unit folks and got reprimanded for that. She didn't mention writing a letter to Tenet herself.
As for the other stuff, I distinctly recall an AP story in around June of 2001 in which there was an alert put out by the gov't that there was seriously something up with Al Qaeda and there was a strong possibility of imminent attacks on American interests here and abroad. I recall that it seemed really significant and scary in tone since we weren't seeing those alerts all the time like now, but the story seemed to quickly fade away and didn't attract attention in the press. Apparently the FAA was notified also but it later came out IIRC that it didn't pass on the alert to the airlines. I think I recall it was not much later after that alert that Cabinet folks stopped flying on commercial jets.
As for press reports, I did see some that said (after the fact in the British press) that the MI 6 info passed on to the US wasn't specific enough so as to have prevented the attacks. I don't recall seeing something reporting the level of specificity you state, either attributed to the MI 6 or later to a CIA report. But here's a bit of a summary from our friends of Fox News about various warnings prior to the attacks: http://www.foxnews.com/story/0,2933,53065,00.html (if the link works.)
And when I saw the Osama tape where he was gloating about the Sept 11 attacks, I took it that he was taking credit for the attacks. The actual date of the attacks may not have been set that far in advance and may have been left to the team on the ground to determine. That in itself wouldn't be surprising in such an operation.
Of course the Administration is now downplaying the hunt for Bin Laden since they've been repeatedly criticized for their failure to track him and Omar down as they promised. They looked a bit silly. Even I could figure out Osama was splitting from Tora Bora while the Afghanis were hanging back and hemming and hawing about a "cease fire." No doubt some legal tender likely was changing hands at that time. Just like now it's not, at least according to the administration, that important whether or not Saddam is pushing up daisies. Just in case, of course, he's not found and winds up enjoying his retirement and watching The Godfather marathons on TBS.