Some general themes as opposed to strictly S3 of ONCE
I see some parallels with Alice and Henry. Both are children who believe in the fantastical but who’s parents (Emma and Edwin, respectively) refuse to believe them.
Without going overboard with this parallel, Cyrus and Alice have a necklace as their symbol. The swan pendant/necklace is a symbol for Neal/Emma
Jafar and Rumple have both referred to the price of magic (as has Peter Pan come to think of it)
Ana’s story is almost the same as Regina’s but takes a different spin. So Regina was forced into marrying the king after she lost her love; Ana gave up her love to marry the king. Ana’s story, then, is a mix of Regina and Cora. I think this means that Cora will see Ana as the daughter she wished Regina had been and will teach her magic, including how to take a heart