I have an excellent book on the Blackbird family, by Landis & Jenkins. In actuality, there are four members of the family:

A-12: single-seat, CIA operated airccraft.

YF-12A: USAF prototype for a Mach-3+ fighter, armed with the AIM-47. Only three or four built.

SR-71A, B, and C: Most prolific Blackbird. The B is a two-seat trainer; the one C was made from parts of an A and a YF-12 that was damaged in a crash (and supposedly, never flew quite right after the "marriage").

M-21: Looks like an SR-71, but had a pylon above the fuselage to launch the D-21 Drone. It had a dismal record with only one successful launch of a drone on an operational mission, but with negligible photo results upon recovery.

While the wings and engines are about the same on all models (except a trainer dubbed the Titanium Goose, which used J75s (F-105 and 106), the nose section and chines of the other models were all unique.

Crashes:

The book lists 19 crashes, but only 4 fatalities:

Ray Torrick, M-21
Jack Weeks, A-12
Walt Ray, A-12
Jim Zwayer, SR-71A

Jim Zwayer I believe was a civilian Test Engineer who died in an inflight Mach-3 breakup (the pilot lived). I don't know if Torrick was Air Force or a civilian. The A-12 pilots were, I believe, CIA.