Further bloated inspection no one asked for ...
Even though she got her first Oscar nod for The Rose in 1979, Midler's primary box-office prime was from 1986 - 1988 (Down and Out in Beverly Hills, Ruthless People, Outrageous Fortune, Big Business, Beaches). She probably was paid the most for Big Business (which underperformed) and Beaches. In those two films, she had shared credit with another female star, in addition to Outrageous Fortune. Stella was her five "solo" gig after this wave, and it flopped (it was an Oscar vehicle and it failed to get award attention, and barely made its budget back). She did a small film with Woody Allen that did okay (Scenes from a Mall). She did an even more expensive Oscar vehicle with James Caan, and that flopped big time. And then she did Hocus Pocus, which didn't catch on right away. She also had the least flashy role in the movie, even though she seemed like the "leader" character.
Goldie's prime was longer, more diverse. After she won her Oscar for Cactus Flower, she was a box-office presence throughout the 1970s in main and supporting roles, working with a lot of top and upcoming directors. Foul Play was huge in 1978, though. And then she followed that up in a big way with Private Benjamin, getting another Oscar nod for one of the biggest hits of the year (where her character drove the story). She didn't make a lot of films in the 1980s. A lot of them were dumb comedies, but she was still working with respected directors and most of them did okay at the box-office where she was the lead or co-lead. That continued into the early 1990s.
Annie Hall, of course, made Diane Keaton 1.0, and she already had the first two Godfathers on her CV. After that, she was making movies--amongst others--where her character drove the story up until the late 1980s. Baby Boom did okay, but The Good Mother didn't do well. I don't think Keaton made a film where she drove the story again until Something's Gotta Give (which resurrected her career and spawned a long line of bad Diane Keaton 2.0 movies). Like I mentioned earlier, along with Steve Martin, it was old colleagues Woody Allen And Francis Ford Coppola that kept her name on the marquees pre-First Wives Club.
I couldn't find anything on Bette Midler's salaries during the 1980s/1990s. Hawn and Meryl Streep were made $4M each for Death (Kevin Kline walked away because he wasn't paid that as well lol). Keaton was paid $1.5M for Godfather III (which was essentially a supporting, do-nothing role). I think Goldie Hawn would have had the upper hand in salary negotiations circa 1995 (if the studio had been willing to pay them what they were worth and still make the movie), but I don't think there would have been major differences in the salaries. They shared the screen equally (running-time wise, I imagine).
Apparently, Keaton's Scott Rudin connection got her cast first, then Midler was cast, and Jessica Lange was originally intended for the third role, but it was rewritten and Hawn replaced her.