My OTE collection only goes back to 1994 with a few odds and ends older than that, so available info is scarce! However, in Rock Stars (Heinz Zak coffee table book), Rachel Farmer's ascents of Let The Tribe Increase, 0% de Matiere Gras and Invitation au Voyage (all 7c+) are dated 1992 (along with her ascent of Raindogs).
Fliss Butler's entry in Rock Stars doesn't mention anything harder than 7b+, but they were onsights. Then there's an interview with Fliss Butler in an old OTE (August '93) that mentions her hardest sport routes as Privilege du Serpent and Mirage (no mention of Rooster Booster), unfortunately without dates.