Turn the computer on, if the HD and PWR led's come on they're wired correctly, if not it isn't going to hurt anything, shutdown and flip the connectors.
Polarity doesn't matter for the reset or PWR switches.
You don't have to use the Q-connector for USB, might make it a little easier if you intend to be removing it often.
There's only one firewire port.
Only one front panel sound connector.