Confusion with winding voltages for a fixed positioned brushless motor
It depends on the driver.  Sometimes the driver provides a holding current that is lower than the drive current, to help ensure the motor doesn't move when you don't want it to.

Yes, the 6 step type is limited to 6 steps.  It can't create more than that because this is saying the driver is only capable of supplying 6 different voltages.  More goes into it than that, but that is the simple version.