MKR Motor Carrier compatible with MKR CAN Shield?

I have an MKR1000, the MKR Motor Carrier board from the engineering education kit, and also the MKR CAN Shield, and I'd like to know if I can use the CAN Shield at the same time as the motor carrier.

From the CAN shield schematic it seems clear that the shield uses the SPI interface with chip select on pin 3 of the header. Looking at the schematic for the motor carrier, header pin 3 is identified as IN1_M3 which then goes to pin 2 of the MC33926PNB motor control IC which drives the M3 motor outputs. The SPI lines are connected to the ATSAMD11D14A-MNT controller IC on the motor board and that has a pin labelled SWDIO/SS which is connected to pin 7 of the header, but via a resistor R16 which is marked DNP.

Does that mean I can use the two together as long as I don't use M3 on the motor board, or is it more complicated than that? I'm hoping to program the MKR1000 from Simulink so I'd be using the Simulink SPIWriteRead block to communicate with the controller on the CAN shield.