If the hag is dead before she teleports, it is easier to save all her saveable prisoners. So make sure to kill her in the teahouse - this way everyone in her lair will not be hostile, which means less work for you.

This will not work though, if you told Mayrina that the hag killed her brothers - after that even if you've killed the hag in the house, some of her prisoners (the masks) will be still hostile after her death.

Go for the kill after you got 5 level or higher, so you could do multiple attacks per turn. Alert perk is also a must here.

0:14 NOBODY has the mask in the inventory. looks like i wanted to edit another line and butchered everything up. what i meant was you can't save the masks except that one girl i showed in the previous video