Acetek used to supply a circuit diagram for the CellOptik 12vdc, however it may be cheaper to just buy one these days as by the time you have made a PCB and bought 1 of each components and attempt to water proof it you will end up spending more.
Home Depot
You can buy 6v photocell dusk to dawn switches from Acetek photocells
1954-1955
1956
No, the voltage rating of the switch is too low.
Get someone who is qualified before you set your house on fire
Use a DPST - A two pole switch.
Unless the switch has a pilot light on it there is need for a neutral connection to the switch.
No. Not safe to do so. The distances between contacts may not be sufficient.
The correct wiring diagram for a 220 volt pressure switch involves connecting the power supply to the switch terminals and then connecting the load to the switch terminals. It is important to follow the manufacturer's instructions and consult a professional if needed.
If you mean 110/240, yes, but there may be a hidden switch to switch it to 240 volt mode. Check the manual.
The output of a 120 volt dimmer switch will be an AC voltage so should not be used on a DC motor.