1st post: depending on how high you push it yes the temps will increase. Do you have any sort of fan speed control software?
2nd post: They appear OK fans, I have no first hand experience with then though
3rd post: The 9700 LED comes with a three pin plug and fan controller, the 9700NT has a four pin plug that goes straight onto the m/board, no need for a controller.
I don't know about the DuOrb, I'd have to Google a review to see how they perform, lets just say I've not seen many people using it, more the Ultra 120 extreme, Tuniq tower and Zalman than anything.