The 4 seater project sounds interesting, oddly getting a balance is going to be difficult, to be a back seat passenger can be a blast, I would not want a car that is too cold for the children, you will find the more you keep the height down the longer the car has to be.
Morgans are quite well balanced, the load is inside the wheelbase and this allows crisp handling with a wide track and fat tyres the car is good in corners, Morgans are never going to be as quick as aerodynamic boxes so the car has to offer something else, handling !
oddly the more upright car will probably handle better, as it would be shorter.
The 4 seater could be quite different if you wished, I actually have a fondness for a drop head coupe - snobmog style, this could be very civilised, it would be very nice with a straight six petrol as these offer the best engine balance a reinterpretation of this more elegant age of motoring would be nice, that said it's your project and good luck.
