She can only read feelings, and can't project, so she wouldn't be able to accidentally add any feelings to the other woman's empathy.

With the shapeshifting aspect of the empathy, if she thought she was a monster because of that, then yes. She'd probably go more than a little furry in reaction to her feelings of being a monster. Webbed hands and feet, and maybe everything else she had back in the days she was in the cage.

Only, she's an empath - hence why Artie can't remember almost aything of his early childhood - so when she's taking them back, she means it and they're going to believe and fight to protect their tunnels.

That would definitely be interesting.

Long, long ago (shortly after being rescued) Meggan had a run-in with Manuel and bit him. At the time, she had extremely sharp, pointy teeth.

So if Meggan's influenced into thinking she's one of the Morlocks, and has always been, she might end up with those again and bite someone trying to drag them away from there, at the very least. She would do what she could to stay with what she thought was her family until someone snapped her out of it.