The only way the he is our Hook theory works and it ends in a satisfying way is if we see a post curse reunion in 7×02.
I think a variation on this that would be ideal and satisfying would be for Hook and Emma to obtain some kind of magic object that shows them their future of reuniting. That way we know they get their HEA, it’s “an emotional curtain call” for Emma since she and Hook are temporarily separating and she can’t go help Henry because (insert reason), and we get to see the actual Hook from the past 5 seasons going forward.
Why does it have to be magical objet? Why can’t it just be a simple FF post curse at the end of 7×02. Simple as that.
This way Hook and Emma know they’ll be reunited. I think it would be more fun for them to be “in on” the flash forward with the audience.