Okay I’m going to lay my theory out here
I came up with this theory that the Wicked Witch needs Emma & Henry to lock the curse in somehow. She either threatens Neal, Snow & Charming or She threatens Emma & Henry either way Hook is sent back to retrieve Emma & Henry and restore their memories. I think the potion is either BF’s memory potion or one the WWW has made using the blood from Snow,Emma and Neal because they are connected to them by blood their family. I suspect once that happens Emma & Henry are brought to EF Or SB after their drinking that potion and their memories are restored they will be like everyone else in SB Cursed but it will take Emma & Henry & Neal to break the curse. I think Emma will find the scroll that she thought Regina destroyed.
I don’t think Emma & Henry can escape the effects of having to go back to the Enchanted Forest with everyone else once this curse is broken.
I suspect that the majority will take place in the EF and that WWW is running things from there
I really think that Hook will bring & Emma & Henry Back to the EF first before SB