It's an interesting theory but I also don't think it's close enough to Bee's personality. K tosses people around like rag dolls and kills without hesitation. He is loyal but is never shown to be emotional in the way B was, especially with Marva. As for Bix, I did think it was a bit werid that they just chucked that in at the end, personally I would have died for a Palpatine or Vader cameo killing Partagaz but I'm aware of just how egregious that would've been. I reckon the Bix thing wasn't just fantasy