Can I commission a Profibus drive without the Profibus connected, or do I need to get the Profibus option card out of the drive?

You do not need to get the card out of the drive. You do need to deactivate the watchdog:

• S400/S600:  in the window "Basic Setup" set "Ext. WD." to zero.
• S300/S700:  in the window "CAN-/ Field Bus Settings" set "External Watchdog" to zero.