The difference between stock and broth is that stock is made by simmering bones over a low flame for hours, while broth is made from meat. Also broth can be sipped on its own, while stock, which usually has a richer, deeper flavor, is meant to be used as the backdrop for soups and sauces.
I used stock made from the carcass of the first chicken we roasted together for this soup. But I think you would have been okay with either store bought broth or stock. (I like to keep a jar of Better than Bouillion organic chicken base on hand, in case Im out of stock, or the flavor of a soup needs a little help. You can find it at most grocery stores.
As for the beans, Im so sorry you had to run out to buy chick peas! You could have used any white beans in your pantry, cannellini, navy beans would have been fine. But, at least you will know for next time!
Kudos for looking up the conversion from fresh to dried parsley!