Exactly, something with a look closer to a car than a truck would have massive aero improvements, with the added benefit of appealing to people who don't like the traditional blocky truck look, which is a sizable demographic.
Plus, like you said, aero and software efficiency can make a huge difference. Ford has way more resources and testing data, so I wouldn’t be shocked if they squeeze out better real-world range than the early estimates. Also, trucks in general are huge bricks aerodynamically, so even small improvements add up.
Well if I had to bet I would say "haste makes waste". In the rush to correct the first problem they may have missed something. Roof? Thick black smoke? Says to me perhaps some stack/exhaust system improperly connected and the roofing material caught fire.