Joan has always been a feminist. I've got all her books / memoirs and she is 100% clear on that throughout. She was iconic in the 80s for battling ageism and sexism. I'm glad I grew up in the 'bitch' 80s era when being an ambitious woman who put herself first was considered a good thing.
As for Jackie Collins - Hollywood Wives & Hollywood Husbands are both about the sexual exploitation and rape of young people by film producer predators - so I'm guessing that she knew something about the subject of feminism as well.