"Product Quality"

Is "Product Quality" a set bonus? It's on some enchants (e.g. Steady). Basically, does it need 10 points to activate?

No, it's not.

Does that one apply to all production that has a quality stat, or just the one needed as it's prerequisite?

There are 3 enchants that give the same 'Product Quality' bonus, and they're all activated by different skills, so I'm assuming all.