But out of the co-founders, especially if we believe Elon's and Hinton's description of him, he may have been the one that mattered most for their scientific achievements.
Honestly, those are not the missing parts that most matter IMO. The evolution of the concept of attention across many academic papers which fed to the Transformer is the big missing element in this timeline.
Not really:
History: https://arxiv.org/abs/2212.11279 (75 pp.)
Survey: https://arxiv.org/abs/1404.7828 (88 pp.)
Conveniently skim-read over the course of the four weekends on one month.