Gavra-at-work, you are so mistaken. It is definitely assur for girls min’HaTorah. There is no malkus, however, as it is a lav she’be’klalus.
To get married for girls civilly (without doing anything) would be a major Chilul Shem Shamaim.
There is a problem with a girl having a roommate? That’s news to me. It’s probably also news to many (all?) seminaries.
If you ignore the part about other legal stuff (which was parenthetical anyway), that’s what he is suggesting. Two girls become roommates. They each adopt a child. They each have a built-in babysitter.
Who (other than you) said anything about getting married civilly?