What kind of cable is required to connect iPad to ur22mkii to unlock Cubasis LE?
You will need the genuine Apple USB camera connection kit.
You can then connect the interface with the USB cable and Cubasis LE will recognize it an unlock.
Is that the only time I would connect the two, to unlock Cubasis? Or is their some functionality with the two connected?
A supported device is required to unlock Cubasis LE.
Once unlocked, it is not required to have the hardware device permanently connected to use Cubasis LE.