In addition, the Day of the Dead does have a quest available -- but you have to work a little to find it. Purchase an Orange Marigold from Chapman, the Day of the Dead vendor, and use the item in the graveyard of your race's capital city to reveal a host of ghosts, including one with a quest to complete. The quest itself is simple, and it'll help you out on those achievements, too -- you will be asked to bake a bit of Bread of the Dead, a recipe that can be purchased from Chapman as well. Give the bread to the ghost, and you've got yourself a Macabre Marionette as a thank-you. This item requires Day of the Dead to use; it isn't a pet, just a fun friend to tag along with you on the holiday.
For those who may not have been able to do the quest last year, it seems this year those problems have been solved. I was able to complete the quest and get my marionette pal just fine this morning. Go nab your achievements, learn a new recipe and pick up a marionette of your own today ... because tomorrow, it'll all be gone!