When "idle", a pure electric motor is not spinning. And, it does not spin till electric current is applied to the coils of the motor.
So, in theory, a clutch (and "gear") to engage a single gear is all that is needed to cause the car to move when the accelerator pedal is pressed. Strictly speaking, this clutch is not needed, but most drivers today assume that something needs to be "engaged" to make a car move, so safest to have that be present.
Plus, importantly, you need to tell the car when you want to go in reverse. Whether this done by a gear system or simply reversing the current is not something I know about ... my approach would be to keep it simple (reverse the current), but not something I know about.
I will ask though ... have contacts working for an electric car company.
Z