Making my control cabinet - what switching controls should I have?

[JAZZCNC]

Mains on/off (NVR switch)

Don't need NVR just straight forward ON/OFF mains contactor switch.

Limit over-ride (so you can jog back off the end stop)

Just use Mach's Auto limit override feature for limits, don't even have them trip the E-stop circuit as limit isn't really an emergency it's positional error and it soon becomes tiresome having to Reset mach and reset drives etc when first learning. After few months you'll hardly touch the limits. Just let the controller handle the limits. Let the E-stop handle the emergency and shut down hardware.

Things that look like they might be useful are:
Spindle On/Off??
Water pump On/Off?? (interlocked with spindle)
Coolant On/Off??

If not controlling Spindle thru Mach then yes but if you are then wouldn't bother with ON/OFF unless you want to add little extra safety for when changing tools.
If using a Spindle with VFD then just let the VFD control the water pump so it only comes on when spinning.
Coolant then yes possibly but Mach got button on screen so if controlling pump thur mach then just use that and keep it simple.

The important things are you use a latching E-stop circuit so then you'll need Reset button ideally with light to show machines ready to go and drives powered up.
Power ON/OFF with light, E-stop button and Reset with light are all you really need. The rest is purely personal choice/convenience.