Both Quiet Girl and Sword Girl are mysteries that will only be able to be solved in Act Three, but that's not in the game yet, sorry :)
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You meet Sword Girl when you first enter the college, and you can catch glimpses of her randomly when you do uniform inspections on the second floor. Her dialogue slightly changes after you bring the "Big Three" under your control too.
As for the girls, well, fingers crossed! War seldom leaves people unscathed...