DRV8428: External control input when VM is not supplied, and recommended value of VM bulk capacitor

Tool/software:

Hi, 

We are considering using separate power supplies for the driver and the external controller.

1. If the EN pin is pulled up to high when VM is not supplied, is there a possibility of failure, malfunction, or voltage leakage?
   
   
2. If there are some input to STEP, DIR, SLEEP, M0/1, or VREF when VM is not supplied, is there a possibility of failure, malfunction, or voltage leakage?
   
   
3. Is there a recommended value and type for the bulk capacitor to be placed on VM pin?
   Since 30 drivers will be powered from the same DCDC, we are concerned that the capacitance will become large and the inrush current will become large.
   The drive current is 160mA/channel, and only up to 6 devices will be driven at the same time, others will be in SLEEP mode.

Best regards,