The invitations were for the lunch after morning services (she'll give a speech after morning services,which is what the girls do at our shul,although they get the same gift as the boys) - this is for everyone. The women are invited to an afternoon service where she will lein - no men allowed. (Or, rather, there can be nine men, behind a mechtiza, but no more.) By this you will know that the girl and her mother are both feminists who enjoy women's services. Note that the mother is known in the synagogue by her birth name.
Since we were also invited, with a separate card, to the dinner on Sunday, we had to send a reply card back. The little preprinted/stamped envelope included for the reply card was addressed to Mr. and Mrs. S. Lastname. Yeah. I'm guess it cost extra to have both names, but it looks so odd from them.