To some extent, yes.
The Seven Sisters were founded to provide high-quality education to women, at a time when women were excluded from the nearby Ivy League colleges. The world has changed in the last century, and women are now permitted to study at most colleges and universities in the US. But sexism in our culture persists, in ways more subtle than its 19th-century manifestations. Some women find that they thrive better in schools where male students are not present, where the whole calculation of "I need to be assertive, or they'll talk over me, but not too assertive, because then I'm not likable enough, and if I wear a dress to that meeting will they assume I'm the secretary instead of the engineer" -- that whole mess, which is in our heads all the time, can just be set aside, and we don't have to think about it while we're trying to learn calculus.
Trans women and nonbinary people are in some ways like cis women in their experiences of the world, and in other ways are different. If you were socialized male when growing up, that's different from being socialized female. On the other hand, being outside of cis male norms is a similar experience. Five of the original Seven Sisters are still women's colleges, and the question they've been working through in the last decade is whether the inclusion of trans women and nonbinary people will still give them the community they're trying to create. All five seem to have decided on, as you say, everyone except cis men and trans men.
I learned a lot from my experience with Smith. When I was younger, my image of women's colleges was that they were for students who followed proper female gender norms, and I didn't want any of that; I chose a coed college for myself. But when my daughter went to Smith, I discovered that the students were throwing gender norms out the window. And of course: in the 19th century, going to college at all was rebelling against gender norms. So as long as you're already in that mindset, you have some common ground with people who are so gender-diverse that they identify as trans or nonbinary.