Musk essentially was the A series, which led to him becoming the chairman and majority owner of the 7 month old company, which at that point just had a handful of guys. He ended up dismissing the original founders of the company before production began on their first product.

Their impact on the Roadster is debatable. Their impact on Tesla, as a whole, is effectively zero.

You can still do that. Just "electric battery car" was not a novel idea in 2003.

Jobs was viewed as the idea guy when he went back to apple, and it wouldn't have been really different if that was his first time there instead of returning.