Quick look over.
Pg1/2
What spindle are you using? This will change what advise would be best.
Earth shouldn't go through the isolator (probably just the way things have been drawn, but earths should never be switched)
You'd need quite a beefy E-stop to handle switching mains voltage directly at the currents involved

Pg3
Those fuses/Circuit breakers should not be there. There should be no switching/fuses of any kind between the stepper drivers and the motors

Pg4
All good.
(note - Power to the steppers should come individually from the power supply as per the diagram, and not daisy chained along the drivers)

Pg5
You'll need to make sure that arduino outputs are capable of power the drivers inputs.
Other than current limitation of the Arduino outputs, there is no need to have all the enables on separate outputs.
Note - I'd have to check the DM manual, but the drivers may default to enabled anyway i.e. be enabled without any power applied to the enable input, and disabled when power is applied to the enables.