It's not a bug. It's a feature. There are various jobs and perks that let you (or monsters) go over your usual maximum HP. Sometimes by quite a bit. The Blood Demon super-perk job comes to mind. There are also perks that let you (or monsters) fight even after being dropped to 0 HP.
As for Amily, yes. She's still found at the town ruins. I'm surprised you're having trouble finding her. I have a hard time avoiding her. Really, I just want to pick up a steady supply of nails, and maybe the weapon and armor racks. But she just won't take a hint.