Re: Batman (1989)
After a bit of research, it looks like most of the newspapers were based on either the May 8, 1947 or the June 18, 1947 issue of the New York Times. If I could get my hands on those two papers, or at least scans of the front page, most of the work would be done and it would SA.
Here's the breakdown by paper:
Batman Cracks Joker's Poison Code! - 6/18/47
Cosmetics Scare in Gotham - 5/8/47 (far left article is from 6/18/47 issue)
Winged Freak Terrorizes Gotham's Gangland - 6/18/47
And there's one paper that Vicki Vale reads that is an unchanged 5/8/47, save for the Gotham Globe masthead.