You are most correct in that your family is going to need to stop giving in to his "begging" behavior in order for him to learn what and when he is supposed to eat. There are many people who "cook" for their pets and provide them with people food, but you need to be careful and make sure that whatever recipe you want to use is approved by a veterinarian. As for helping him become more interested in his dog food, I would try a variety of things...try basting the food with some warm water to make a gravy....you can also try putting some of the kibble in the freezer as this gives the food a little bit different texture. Finally, many dogs can be enticed to eat their dog food with a little bit of honey on top of it.
Many pet owners are also concerned about your second problem...running off and accosting people who come to the house. You are going to need to "start over" with his training and work on basic commands ("sit", "down", "stay") so that he understands that he needs to behave this way in order to receive praise, treats and attention from you. A visit with a veterinary behaviorist or a certified pet dog trainer might be a good recommendation...just be sure to avoid anyone who says that the "dominance" theory is their recommended course of action!