The Ox was a good read, though not much in the way of bass techniques or how he revolutionized the instrument, more on how he was probably the best customer Harrod's ever had. Agree on Lesh's Searching For the Sound. He does give some good detail on the intense rehearsals and exercises the band engaged in in the early days that led to their experimentation sonically, rhythmically, and how they developed exercises to play different time signatures and meet up a certain number of bars in.
Standing In the Shadows of Motown is educational, but also biographical as it centers around James Jamerson's impact on Motown. There's a bio of Duck Dunn with transcriptions as well called Soul Fingers. I have it, but haven't read it yet.
Unfortunately, there's probably not a huge batch of bios on the session players you're looking for, but there are documentaries worth checking out: The Wrecking Crew features Carol Kaye and Joe Osborn; Muscle Shoals features David Hood and the other Swampers; and Standing In the Shadows Of Motown, of course, features the Funk Brothers and keeps focus on Jamerson, but also includes Bob Babbitt, who plays with the band in the concert scenes. And of course the Jaco documentary is quite good, as well. And An Ox's Tale is a much more bass focused examination of John Entwistle's playing, including much bass porn.