An ambitious plan announced last week to return Lolita, a killer whale held captive for more than a half-century, to her home waters in Washington’s Puget Sound thrilled those who have long advocated for her to be freed from her tank at the Miami Seaquarium. But it also called to mind the release of Keiko — the star of the movie “Free Willy” — more than two decades ago. Keiko’s return to his native Iceland vastly improved upon his life in a Mexico City tank, but he failed to adapt to the wild and died five years later. Advocates say their experience with Keiko will inform how they plan for Lolita’s return.