No, a bad engineer is one that takes no risks ever and end up doing nothing of consequence. His risk taking is the sole reason SpaceX exists.
Not in the least. SpaceX hires a lot of rocket scientists who are industry experts. They're more agile than the entrenched players since Boeing/Lockheed legacy space programs weren't efficient but SpaceX has relied upon expert consultation and expert advice from folks in the industry to build their rockets. I don't see them as building from first principles at all, they're building on what's come before standing on the shoulders of the rocket engineers who've come before.