#i could be wrong i don't understand crisises very well tbh i just read the wikis and call it a day

[danny-chase]

Do the all or any characters in post-crisis remember pre-crisis? And what do they remember in New 52 and Rebirth (and do only heroes remember something or also civilians)?

Post and pre crisis is tricky because some characters made it through relatively unchanged and others had their histories completely rebooted. From the wiki:

"Wolfman and Pérez teamed again to produce the History of the DC Universe limited series to summarize the DCU's new history.[8] Many of DC's characters had their histories rebooted. Wonder Woman's comic was relaunched entirely by Pérez, Wein, and Greg Potter.[41] Superman was first re-envisioned in the limited series The Man of Steel by John Byrne; his comic was retitled The Adventures of Superman to make way for a new Superman series.[8] Batman was minimally affected by the reboot, and his comic was not relaunched. However, he was still given an updated origin, courtesy of Frank Miller.[10] In addition, Wally West replaced Barry Allen as the Flash, the Justice League's roster was changed, and characters DC acquired from other companies, such as Fawcett Publications and Charlton Comics, were integrated into the DCU.[22][42]"

They remembered some stuff (ie: Dick remembers spending years working with Bruce) but some of the events were changed (ie: now he remembers Bruce firing him after getting shot by Joker instead of just leaving).

New52 wasn't the cleanest cut for a reboot. The timeline was different in the new universe so they didn't remember events from the old (at first) however which events happened was somewhat confusing. For example, Dick remembered being Batman to Damian's Robin, but doesn't remember Blüdhaven. Tim was never Robin, so the conflict between him and Damian made little to no sense (and made Tim look petty). Even more confusing were things that directly contradicted one another - the titans supposedly lost their memories of being a team, yet Roy and Kory reminisced about being Titans with Dick over in rhato. Rebirth was a soft reboot intended to bring back more elements from the old continuity that people liked, not necessarily in the form of memories, but could have characters glimpsing past lives - Cass and Steph were shown images of themselves as Batgirls and Steph as Robin, but they didn't get to really remember those lives.

Current status quo is infinite crisis which says everything is canon. Which. Characters have their memories back but that doesn't necessarily mean they're acting like it. Cass and Steph remember being Batgirls now but the way they act in their batgirls title is so far from their original characterizations it makes no sense. Dick remembers being a cop but apparently doesn't remember poverty exists (literally right after being homeless as Ric). So in practice: everything that the people writing the characters have read is canon. Good thing DC writers are known for doing their research and attention to detail /s