To answer the OP, it’s become common to use the term rebbtzin in a nonliteral way, e.g. “I am inviting you and your rebitzen to sheva brochos” (CS objected to that, but it doesn’t bother me, since the term rebbetzin doesn’t really have that much importance to me).
Using the term for a public speaker whose husband isn’t a rabbi sort of expands that.