Why does the unicorn in the ending of BR final cut add more to the idea that deckard is a replicant? i know gaff was fiddling with that stuff all the time.
There's a brief scene earlier in the Director's Cut, which is extended in the Final Cut, where Deckard "dreams" about a unicorn. People take the origami unicorn to signify that Gaff knows about Deckard's implanted memories and dreams, just as Deckard knows the spider memory belongs to Tyrell's niece, not Rachael. Scott wanted the unicorn to be in the theatrical release, but he was overruled.
More literally, it's an indication that Gaff was at the apartment and could have killed Rachael--and maybe Deckard--but chose to spare them.
But the ambiguity is there: Deckard hears Gaff's words again ("It's too bad she won't live.
But then again, who does?"), nods as if understanding something, and leaves with Rachael for their life together. Gaff also says "You've done a man's job, sir," which could be interpreted in two ways: you have done a fine, masculine, upstanding job; or you have done the job as well as a human would, wink wink.
The movie doesn't make a clear judgment about whether Deckard is a replicant, because ultimately, it doesn't matter; his experiences hunting the Nexus-6, and watching Roy's last moments, has shown him that humans and replicants are emotionally indistinguishable (as tears in rain!), and equally "human" in their way.
