SRD under Free Actions in Combat:
Annoyingly, it is swift actions that make free actions kind of murky; the wording of free action doesn't explicitly say when you can or cannot use them. Just that you can. Swift actions state that you can make one per turn on your turn whenever you'd be able to make a free action. Swift actions use what is defined as a free action, but free actions are undefined explicitly. (Ugh, Paizo, you cannot use one action to define the limits of another!) I set it as a free action because I did not feel it should prevent you from using a counter and/or Deathless Defenses as necessary. It should probably be redefined to an immediate action, but it's because it's in the rules hell that is Pathfinder's swift / free action writing.Free Actions
Free actions don't take any time at all, though there may be limits to the number of free actions you can perform in a turn. Free actions rarely incur attacks of opportunity.
2) Yes, yes it does.
3) Yes, and you're finding it hard to justify throwing a weapon around in a spinning fashion so that it would return to your grasp but a shield is not outside of that realm of probability? Ya know the dude next to you is getting power from his god to raise the dead and that lady over there is breaking the fundamental rules of reality with finger wiggling and bat guano, right?
4) They've been renamed "Martial Traditions" and we've added some for the first book, and more in the second. I'd like to see it expand beyond martial disciples to see Psionic Traditions or Akashic Traditions as well.