To what extent can we consider the post-fall events to be almost canon?

I’m new to the fandom and sometimes feel confused about what is believed to happen after the fall, my question is just to distinguish what comes from the creators and what is merely fandom speculation.

like, confirmed that Hannigram survive, but is the idea of them fleeing to Cuba just a reference to the book? Did the director say anything about this as well? And is the interpretation that Hannigram were together in Bedelia’s final scene only a theory? I’m open to other comments made by the show’s team too.