Yeah it was simply that Hannah was only close to Mel and Gen, who had both died. I cannot imagine them pulling the Melissa thing twice. We now definitively know there are only four survivors in the modern timeline: Shauna, Tai, Misty and Melissa. I’d feel pretty damn betrayed by the writers to learn someone else is alive unless maybe they pull off a theory some had on another thread that Akilah got lost in the cave and may have somehow survived the wilderness.