4 wheel very light vehicle technology choices

I am thinking about a 4-wheel single-seater vehicle that is inside the L6e rules. These are max 4000W and max 45 km/h. This will be a road-legal 'moped' with cheap insurance/no tax.

For the layout I want to have a cyclekart type of body (torpedo-like hull) with the 4 wheels all on wishbone suspension. Wheels are 26" carbon bicycle wheels made by Aerospoke. Weight should be below 250 kg with 1 driver included. Max distance ~120 km.

Now my questions are:
1. Which 4000W motor should I use?
2. Can I use a beltdrive from the motor to the axles
3. Which size / how many teeth for the gears on the motor and axle side
4. What differential do you recommend?
5. what kind of drive shafts and connections?
6. Voltage of the battery packs and how many