Are heinz 57's good starter dog's?

It all depends. For instance, a Terrier mutt could be more hyperactive and require more work than another. Think about the lifestyle of your family. How much time you can exercise the dog, how long the dog will be left alone during a typical day, size and shedding requirements, grooming, whether you mind barking or not, etc. Based on many things, look for a dog that would fit in properly. A shelter volunteer or rescue worker can help you find a dog that will suit your lifestyle and fit in just great. Good luck and congratulations on getting your first dog!