"I doubt a pregnancy would make her soften."
She's not getting softer, she has morning sickness. It's a pregnancy thing. Google search; first result says "Morning sickness refers to the nauseated feeling you get during the first trimester of pregnancy."
As for Kalani being a plant by the Mallers, there are more than a few holes in that theory. One, he said he was from Hawaii. We have no reason to disbelieve that, and Burt said they saw a crashed Hawaiian Airlines at LAX. Kalani said that the landing was messy, in more way than one (airplanes are loud, zombies are attracted to sound). Kalani said only three of them made it off (we are assuming Hannah is one of them) and the other tower rescued them. After that, he was there for a few days and then the other tower fell (figuratively, not literally fall like our tower). Then, he was found in the Arena and has been with our survivors ever since.
So he was either lying about where he was/when, when it all adds up perfectly, or he isn't a plant by the Mallers. (Yes, I know he might be lying. But he's being accused with almost no factual evidence. Unless I missed some major fact.)
Big fact up ahead: We have NO evidence that Hannah was the girl that was shot. We know nothing about her except that she was Kalani's girl.