Mirina never goes to the tavern. Ask the nuns about it. If there is no such choice, then she is waiting for you in the field during the day (not in the grove, but in the field)
Near the executioner (gallows location) there is a notice board. There are advertisements for Trader and Blonde Nun.
The tavern owner loves booze.
Just complete the rest of the quests and everything will fall into place.