Hi Allison,
yes, for unused digital pins, it is recommended that software disable both the input buffers and the output buffers of the pads in the Pad Control Register for the pins. In addition, the weak pull-down device should be enabled. This keeps the pad in a safe state under all conditions.
For analog pins, it is recommended that they be pulled down to VSSA (the analog return path to the MCU).
BR, Petr