On the last point: Hermione almost certainly was false memory charmed twice; H&C would have removed the memory of their final conversation and replaced with with something innocuous at the same time as he implanted the false memory of casting the blood-cooling charm, so as to not leave a suspicious gap. He might also have implanted false memories immediately after the groundhog day attack, either to cover up the time gap or to not have Hermione wandering around with an extremely suspicious memory in her head (If Dumbledore or Snape had seen the memory of H&C, or his less-creepy disguise, they probably would have been fairly suspicious).