She mentioned the mermaid in Skin Deep, if I’m not mistaken. However, there are mermaids in Peter Pan although I highly doubt she’s referencing them, in all likelihood, she’s talking about Ariel.
It is possible Atlantica is part of that sea, but seeing as it’s water, my mind wandered off & started thinking about what August said about water ( having magical properties ) … makes me wonder. How all we know, water could also be used as a portal, I think Jefferson’s hat allows you to choose which world you’ll end up in via the doors. Whereas other methods are probably less specific, in particular, the wardrobe that Emma was placed in, I mean, they didn’t know what world she’d end up in.
After re-watching ‘Hat Trick’, I’m pretty convinced that anyone could use the hat, it’s just the fact that for it to work – 1) the hat must have magic & 2) You must follow the rules which the magic imbued in the hat lays out ( ie – for Wonderland’s Looking Glass it was – two enter – two leave – & Jefferson clearly states that not his rule, it’s the hat’s. )
So that makes me think that Jefferson had to trade something in order to get the magic for this hat in the first place.
( On a completely different note – I wondered upon re-watching the episode *upon a 3rd viewing* if perhaps Jefferson’s wife was even from FTL to begin with. Upon which I had the crack-pot theory that since Grace is Grace in FTL & Paige in SB – perhaps Jefferson met Grace’s mother – Alice in Wonderland & used the hat to bring her back to FTL. … just a fun little theory. It might also tie-in to who the Red Queen is – because in the original tale ‘Through the Looking Glass’ – Alice does stay for an amount of time & rule over Wonderland. )