You still need to sacrifice a heart to make it happen.
Loopholes upon loopholes.
This is a season fraught with talismans and symbolic objects. So let me first just say this: if they go this route, it’s sloppy writing and trying to create more loopholes in something that was once definite. So now that I’ve shielded myself from angry people…
We’ve seen that you can use an object that is infused with a characteristic to stand for that trait. Charming’s sword is not actually his courage; it’s a symbol for it. The episode the Jolly Roger was basically (even for me, a HARD CORE SF as @Obisgirl once called me, love you) that Hook’s ship is a big metaphor for Emma and the love he bears for her. Therefore because this show does not posses enough internal logic, we cannot say that he cannot use the JR as a heart. The JR has been infused with the love Hook bears Emma and therefore is a metaphorical heart, not a literal one. They keep saying you must sacrifice a heart, but they don’t specify if it is a literal one or not.
My money is on Hook being tricked and keeping quiet because he’s ashamed that he got taken in by Greenie.
Other possibility: Glinda sacrificed someone she cared about?