Actually, if I recall correctly. I think one of the ports stopped working. I recommend trying both before giving up on this one. Sometimes you might find that although it might not work with one cable type, it might work with the other. Try both USB and Thunderbolt. Hope this helps.
This really depends on what software you are using but a 7200rpm drive should be fine. Something like 4K video might be an issue, but you should totally be fine with audio.
Two 3.3 mm silver Phillips screws on either side of the SuperDrive.
Be aware there are two of these on the bottom (if the slot is facing you) screws close to each other, one is for the actual drive assembly itself and the other is attaching the drive to the Mac. Beware you choose the correct one.