Prometheus Bound Theme of Fate and Free Will

Like practically every Greek tragedy you've ever heard of (and most of those you haven't), Prometheus Bound is obsessed with the difference between fate and free will. (These questions have been known to cause acute mental dizziness in generations of readers—so don't be alarmed if Prometheus Bound has the same effect.) Here's the issue: most of the characters express the view that everything is fated. And yet, most of them also keep telling one another to do various things. But why tell people to do things if they're fated to do them anyway? And why waste your time complaining or asking for help if there's nothing to be done?

1. Are fate and free will in conflict with each other in Prometheus Bound? Or, is it possible (in the world of the play) to know the future, and still have freedom to act in the present?
2. How much is the question of fate and free will related to knowledge? For those (unlike Prometheus) who don't actually know the future, does it really matter whether anything is fated or not?
3. In the play, Prometheus says that Zeus isn't all powerful, but is instead bound by fate. Seriously? Do we believe him?
4. Hephaestus claims that he isn't acting freely when he chains Prometheus to the rock, because he's following Zeus's orders. Is following Zeus's orders the same as not having free will, or is Hephaestus just using that as an excuse?

The issues of fate and free will are more important to gods, because humans are too weak to have free will.

If fate rules everything, then Hephaestus's claim that he's just following Zeus's orders is accurate. On the other hand, if humans can act with free will, then Hephaestus's words might be an empty excuse.