The first woman to compete in the TT was Inge Stoll (Ingeborg Stolle-Laforge), in 1954. She was Swiss German, but raced with a French driver (Jacques Drion), and, sadly, died in the Czech Grand Prix in 1958.
I don't know about the first female passenger with an ACU licence ... lost in the mists of time.. Fred Hanks wife passengered, and I hope to track down more from that generation for my book.
To tell you the truth, in those days, some passengers had no licence, they just said "I'll do it" and off they went. The programme just said A.N.Other!