As far as Securitas having performed negligent security, obviously I don't know what happened, but it appears as if they were operating within the realm of what they were asked to do. The attackers used knives, and apparently they were razor blades attached to some piece of plastic. Since personal hygiene kits and swiss army knives had been allowed into airplanes, I don't think Securitas could have stopped any of the weapons from having been smuggled. I think the problem here was that the flight attendants and/or pilots were not properly equipped to deal with hijackings. Some pepper spray would have helped, as would have a solid door between the cockpit and cabin, like in El Al.
Many foreign companies perform various services, including security. As far as the Sikh company in Oklahoma, it would have probably been nearly impossible for any security company to do anything with a street right in front of the building. The Dutch government basically runs Kennedy Airport in NYC.
The WTC was targeted because it represented American might. It was not targeted because of some SEC investigation or for any other reason. They brought down both buildings, and involved around 10 suicidal bombers.
Hillary might not have any love for Barbara Olson, but Barbara's book about the last days of the Clinton presidency is done, and will be printed and made available in bookstores. While she won't be around to promote the book on TV, Hillary won't be able to continue the personal attacks that were used before when people attacked them. On Amazon, Barbara Olson's Hell to Pay has shot back into the top 20, despite the fact that the book had more or less run its course.