I think Granny, Red, and the dwarfs + Anton will stay behind.
The people going are all related to Henry and the ones who aren’t directly related to him have a strong connection to the family and can help (ie: Belle being there for Rumple + she’s practically Henry’s step-grandmother, and Hook having known Bae in the past and wanting to help his son + his has the ship for them to use + he was involved with Henry’s grandmother as awkward as that is for me to admit, so…they’re all connected back to Henry). The rest can stay and protect the citizens of SB for them while they’re gone.
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Keeper of Hook's Trenchcoat.