Right Wonderland was another world but traces of Wonderland does not exist in SB. Except Jefferson and who knows how he got to SB we think curse but do we know for sure? The answer is no but he certainly could have. Traces of FTL does exist in SB strange isn’t it? If it is suppose to be a whole new world but yet traces of the old. Think of who enacted the curse….Regina. Did she create it or knows what the entire result was going to be? The answer to that is no because had she it would have worked the first time she tried it. Rumple created it and he knows all about it I bet. If FTL was destroyed why not destroy everyone in it as well? He needs everyone in FTL to help in whatever he intends to acomplish. He wants to find Bae and it seems everyone is a part of it. Regina’s goal is to destroy everyone’s happy endings and Rumple’s is to find Bae but is destroying FTL part of it or can it just be a by product of their goal. Either way if they can both do it without destroying FTL they’d do it.