I think is what happened- the block stuff from season 2
first rumple tells regina gives the curse to her
then she trades it to malicent for the sleeping curse
then when rumple suggests it, regina tells snow white and charming about the curse on their wedding day
that night regina goes to malicent and steals the curse from her
over the next 9 months ( based on snow begins pregent) regina gathers up ingrediants for the curse and tries to enact it she also sends to hook to go kill her mother and brings her back, then when she fails with the curse, she goes to rumple who was imprisoned over the last couple of months and then kills her father after her mother then uses his heart to enact the curse.
Keeper of Swanfire's dream catcher, the Blue Fairy Plot Device, the contact name "Her", the lanyards, the trigger, the Netherworld room and necklace, Charming's quote on Thanksgiving, and PP's pic of Henry