If it is unfiltered you will need pectic enzyme.
Check the ingredients, it should be something like, (Apple Juice, Absorbic Acid[Vitamin C])
Potassium Sorbate will inhibit fermentation.
Well, sure. But I'd wager that most people are aiming for clarity. Even though people who make wine know that a little haze doesn't affect wine, the uninformed think there's something wrong with it.I wouldn't go so far as to say, "need." But if you want it to be clear, then you will absolutely need pectic enzyme. Sometimes I like to keep it cloudy to make it rustic looking.