I'll answer the ATA100 question first. Yes. However, it will run at ATA66, but there should be no problem. I have an ATA100 drive running at ATA33! :Q
As for the stray wires, I used electrical tape and wound that around the wires, and routed them underneath the mobo and along sides the edges of the case. The rubber hose type things may be split loom; I dont really like that but a lot of people use it and are content with it.
Just regular zip ties and twist ties work wonders too.