Here are the 2019 hints for the Quest [and what they meant]:

Hint 1: The tag is the dog’s, but the dog is a red herring.

Hint 2: A first. [A is the 1st letter]

Hint 3: 15th. Oh! [O is the 15th letter]

Hint 4: 8 giants and 5 dwarfs observed to the west. [Planets observed at Planetarium in Museum]

Hint 5: Pete Reds. [Rose]

Hint 6: What I rode in high school sports. [the bench]

[Tag was hidden under a park bench on North Mall east of Public Museum]