I'm not sure 7 people is representative of the goals of the world, although perhaps representative of where your concept was posted, and who read it.
If it is a local commuter, I'd still consider electric, although that could very well double the price when adding in the cost of the batteries.
Your car looks a lot like the Aptera... which got quite far, but never quite made it to final production.
https://en.wikipedia.org/wiki/Aptera_2_Series
Ohh... it looks like they are back.
https://en.wikipedia.org/wiki/Aptera_3
Not a company I would send money to until they actually have cars on hand.
It looks like there is another company in that genre
https://www.eliomotors.com/
Is that where you are getting the 80+ MPG from?
If you make your car very low to the ground with low mounted weight, then you will get some intrinsic stability. That may well be a benefit of going with a Battery powered car. I think tilting on turns can be achieved a bit with steering geometry, and should help considerably.
Your images on the web page show a sleek vehicle, but tall and narrow. And, I think stability would be compromised.
Nonetheless, the Aptera and Elio use outriggers. A good idea for stability, but I have to wonder if they would be prone to problems with impacts.
For me, I would require at least a 100 mile range, and 55 MPH for a vehicle. I can barely go anywhere for < 40 miles, and a bit of a buffer will help if I choose to do a side-trip, or with battery longevity.
2, 3, or 4 wheels? You'd have to decide how to do starts/stops if you built a fully enclosed 2 wheel vehicle.
4 wheels oriented on the 4 corners of a rectangle may well be the most stable design.
Ultimately the choice of 3 or 4 wheels may be a licensing issue. 3 wheels gets licensed as motorcycle. 4 wheels gets licensed as a car (or NEV with restrictions of use). And that will heavily impact your build and safety designs. Unfortunately building a 3 wheeled "motorcycle" brings about other laws such as motorcycle endorsement on the driver's license, and potentially wearing a helmet.