I would really appreciate any help you could give us. From these comments and other things mentioned in your letter, some things are obvious. They do tend to yak a lot. Training is imperative, so you have to stick with it. If you don't have control, you will probably prevent your dog from being socialized with people and other dogs, and lack of socialization is a major problem.
Dogs are unique, just like people.
Not just unique as breeds, but unique as individuals. So now you have an energetic, sweet and sassy schnauzer, and his responses will be different than your previous dog. There are many types of aggressive behavior, and without discussing your dog with you, more specific advice would be based on assumptions rather than facts. Two years ago, she had a urinary tract infection and was wetting on the carpet. The vet says it's a learned behavior.