Another reference book coming.
Marvel Studios Cross-Sections
https://www.penguinrandomhouse.com/books/787698/marvel-studios-cross-sections-by-liz-marsham/
Is it fair to even consider Sandman / DBD part of post-Crisis Earth-19?
Matthew Cable dies in the Swamp Thing show, and while he appears reincarnated as a crow in Sandman - they are vague about his death to where he just states something along the lines of "I can't remember how I died, but it...
Gunn said Superman was the same age as Corenswet. Corenswet was 31 during filming of Superman.
But yeah, 1992 is a leap year, like you said. Had that in mind too. :)
Another reason by the Blue Beetle movie isn't DCU is because the LexCorp logo is in the background establishing shots of the city it's set in.
The post-credits scene might be, assuming the movie's events happened almost the same in the DCU with some differences, or we could take from that Ted...
I think it had to do with my take on DCU being the "new Earth-1", but that isn't factually proven, so I didn't put that in the timeline reasoning.
The timeline reasoning on page 1 is unbiased gathered information.