There will be one missing Fable you have to go back and get in the last chapter. It involves the choices of ripping off Grens arm and choosing not to. Also in chapter 2 make sure to grab the Bluebeard file off your desk in your apartment before you talk to the pig. This is a missable Fable.
After the credits rolled I went to 'Play Game' and chose to 'Rewind' to the final chapter of Episode 1. You can choose a separate save file as to not disrupt your own story line and choices. You'll have to replay the last section which takes place in the bar. If you missed the blackbeard file you can do the same thing and rewind to chapter 2 selecting a different save file.
You'll need to make a decision when fighting Gren. At the end you can either choose to walk away or to rip his arm off. The second time through I ripped his arm off and unlocked the final book entry. The achievement unlocked shortly after I made the second choice, and I was able to quit out right there.
If you walk away you unlock bigbys mercy; if you rip grens arm off you get bigbys vengeance.