So who is the Tin Man? Regina would be an obvious association with hearts, but since Regina is apparently the main target of the curse, I don’t think she would also be one of the other characters. My next choice was Snow since she certainly has a good heart and the spot of darkness revealed when Regina ripped out her heart could also be a bit of foreshadowing. I initially ruled out Henry because they already dealt with him losing his heart in Neverland and Regina cast that spell to prevent anyone from taking his heart again. But now I’m wondering if I took the heart idea too literally and Henry might be the Tin Man after all. What if Zelena arranges for Henry to meet a little girl named Dorothy and he develops a crush on her so he “loses his heart” in the metaphorical sense? We saw the storybook surrounded by the smoke at the end of “Going Home” so we expect it to appear again in Storybrooke. The book might be the symbol of his heart. Henry might discard the book for Zelena to take if Dorothy teased him about being too old for fairy tales.
Personally, I think it’s Neal who will be the reverse Tin Man. His motivation is his love for Emma and Henry and Rumple. The Tin Man thought he didn’t have a heart but of course he was the most emotional of the three. And, in the movie at least, the placebo the wizard gave the Tin Man was a heart watch. I will admit this is stretchy but it’s possible the Swan Pendant, last seen in Manhattan in the bar scene, is Neal’s totem and that’s what Zelena takes.