Very late reply, but I'm so incredibly pleased that no one predicted our DEKE SLAYTON WITH A STEEL CHAIR twist.Seriously that is such a good edit.
Now I'm just tryna figure out what your Apollo 19 and 20 crews are gonna be. You mentioned that backups would now become primes 4 missions ahead, not 3, so that puts the OTL Haise/Pogue/Carr for 19 (especially considering Haise already walked on the Moon on 13 ITTL) and Roosa/Weitz/Lousma for 20 (and you have Skylab running concurrent with lunar missions in your timeline so Weitz is unlikely) out of the question.
I'm just gonna take a blind jab in the dark and go for Chaffee (CDR), Engle (LMP), and McCandless (CMP) for 19, and McDivitt (CDR), another scientist-astronaut for LMP, maybe Anthony England since he was a geophysicist, and Lind (CMP) (even though Lind was more likely to have been an LMP IOTL) for 20. I base this on nothing and will take no questions.
EDIT: Ninja'd by the very author of that post!