Got a little more details on the Nixon years. Seems like there's not a ton of information on who else was considered beyond Haynsworth and Carswell. Carswell was a recommendation from Burger. Similarly, Blackmun was also a recommendation from Burger that an exhausted Nixon just went with since he was a northerner. It seems a shockingly small amount of thought went into the Blackmun nomination with Nixon erroneously assuming he'd have a similar jurisprudence to Burger, with Nixon even introducing him as a "strict constructionist."
For the vacancies created by Black and Harlan, Nixon was only certain for Lewis Powell to replace Black's seat. For the Harlan seat, while he thought about Robert Byrd as a basically impossible to vote down nominee, Nixon ultimately didn't really strongly consider him. (In addition, the shortlist that Nixon sent to the ABA was all a ruse, meant so that the ABA coudl reject Herschel Friday and Mildred Lillie and Nixon could cynically blame them for being against a southerner and a woman) Instead, he really wanted Senator Howard Baker, a conservative he felt could be on the court a long time and eventually be Chief Justice to match the much older Powell. However, it was Baker's refusal to really say whether he wanted it or not despite Nixon's constant insistence. It got so bad that the day before Nixon was supposed to announce the nominees, Baker still had not made a decision. That's when talk about Rehnquist was pushed by John Mitchell and Richard Moore. Nixon wasn't really interested until he heard about Rehnquist's class ranking and then, with Baker still having not decided, decided to go for him.
Rehnquist was genuinely quite shocked by this. When asked if he was being considered by a reporter, he replied "Why should he? I'm not a woman, black, or mediocre."