This discussion may contain spoilers!
In the episode 2 trailer, Clementine asks the group who the person at the door was.
Carlos says "One of the guys we were with before."
Now I don't know if anyone else picked this up, but Carlos is hinting that the door-knocker is ONE of MULTIPLE people they used to be with. So they didn't just kick Carver out, they were seemingly a group with the other characters we've seen (allegedly named Troy, Johnny, Mathew and Walter).
I only just noticed that today. I was too busy thinking about whether the guy who knocked was in fact Carver (or Heisenberg) that I didn't realise Carlos was making reference to multiple people.
EDIT: Vivec has notified me that Pete says that Carver is a man in the kitchen scene, so this following bit is false:
Also they never reference Carver being a man, so they could be a woman or even a name for the group that the cabin group split from. Nick says 'Think about it - you're Carver, what do you do?" He doesn't actually say Carver is one person and it could be used in reference to a group.