1) You won't damage anything by hooking those up wrong, not sure about the polarity, but don't be afraid to try it and see if they work
2) Just connect the 20 pin
3) YOu mean jumpers on your drives? You need to make sure they are jumpered correctly. They don't come from the factory that way.
4) You shouldn't have to do anything in the BIOS, but you won't know for sure till you start it up
Associates Degree in IS
Studying for Network+