I'm looking at these with a 4" brass caliper held up to my screen. YMMV The Beetle has a wheelbase measured at 2 1/4" and a cowl height of 3/4" — 9/3. Your drawing measures 4 1/4" and 1" — 17/4. If that's a small-diameter wheel, then it's an even tinier mannequin (blue dot to top of head = wheel diameter suggests 5' figure). I know it's a lower seating position, but still...
If you move the 0° camber point forward, there would be more curvature in the front facia and less needed in the solar panels. Are the windscreens transparent over the solar panels? You could have a legal-height light in the front of each one and the melt-the-roadsign-reflectors lights low on the front or they could pop up out of the headrest fairing.
I'm curious about transmission you mentioned. My thought was to get a small enough motor that you could take the gearset and nosecone off the transaxle and stuff it inside the case.