First playthrough, I missed two survivors. I didn't get the achievement for having collected all survivor combo cards.
On the second playthrough (having restarted my first playthrough), I just got through saving both of the survivors I missed the first time. Neither of them gave a combo card, though. So I'm still lacking that achievement.
In order to narrow down just what's going wrong here, I think I need a list. For now, here are the cards I'm missing, most (all?) of which are not survivor cards, though I don't know which are, if any:
From memory: Blambow is from a movie poster, Wingman you make yourself.
Not sure about the others. But you can cross off the two above ;) --- Maybe when the door of happiness closes, another opens, but we look so long at the closed door that we don't see the one which has been opened for us.
Blazing Aces and Exsanguinator are both gotten by getting all 4 Tape it or Die survivors back to the safe house. You have to meet them during Case 4 and then save them during Case 7. --- See You, Space Cowboy! GT: Linkin10362