Tinkerbell was a fairy, not a princess. She’s no more a Disney princess than the Blue Fairy (Pinocchio) or the three good fairies Flora, Fauna, and Merryweather (Sleeping Beauty). They are Disney characters, but not princesses, princesses are always human.
Tinkerbell was marketed as a “Disney Princess.”
https://disneyprincess.fandom.com/wiki/List_of_Disney_Princesses
As far as I know they never declared a king or queen.