Minnie is a limited-time character that was released on November 14, 2018, as part of the Thanksgiving 2018 Event. She is unlocked upon the placement of the Mattress King Dinner Table. Together with the Mattress King Dinner Table, they were the third prizes to be won in the event.
She was the only non-premium character of the event.
Her questline didn't start upon her unlock, but at the end of the main event's questline Blood is Thinner Than Gravy.
Just like Everyman, if being gained during the period upon the event ended, next part of the quest Blood is Thinner Than Gravy didn't come after, her own questline didn't start and she got no job unlocked (except for group jobs from some buildings).