Gotham as far as I know is its own continuity with differing origin, status and ages for the characters, like how for example Barbara Kean is never evil in the comic and Harvey Dent is the same age as Bruce. So I don't think there's a comic continuation.
As for timeline depend on continuity. There's the Post Crisis Era, the New 52 and Rebirth, the latter ones incorporate older continuities with some differences.