I actually first entered the Hag's cabin through the mushroom ring from the underdark. I completely bypassed her without dialog, stealthing, all the way to the cage room and her 'lair' / loot room. I took everything then used the mushroom ring to return.
I then proceeded to talk to her. She sent Mayrina away. I went back through the mushroom ring to her lair and let Mayrina out of the cage using the ball. She seemed pretty clueless. She just said something like "What? Are we not in the tea room anymore?" and stood still. All dialog just repeated the same things. I also broke the cage to see if I could get things moving, nothing but reduced her attitude to me.
I then went *back* to the hag and attacked her. She 'broke' the illusion on the fireplace and left. I didn't finish combat and dashed to the mushroom ring to get down to her lair and skip the fights with the peons. The hag wasn't in any of the lair or cage room and Mayrina was unresponsive still.
It seems like if you free Mayrina before revealing the hag, or somehow skipping other triggers, the hag doesn't show up in the lair/fight room.
