Sure, you can make falafel from a mix but frankly, it's a far cry from authentic falafel. This is the best falafel recipe I know of. You can find dried fava beans in Middle Eastern grocery stores and some supermarkets. Serve with pita bread, tahini sauce, lettuce, and other chopped vegetables.
Do not substitute other beans such as kidney beans or cannellini beans for the dried fava beans and chickpeas. In their raw or undercooked stage, these other beans contain the toxin phytohemagglutinin, which causes severe illness.