From my experience with both breeds, mixing those breeds together your going to get a VERY hyper and big time barker. The wheaten terrier is so active, at work I must have thrown a ball for 30 mins. and then let him play for 30 mins with other dogs and he was still wanting to play. Schnauzers are the exact same way.

Now I am not saying there bad breeds, but not a breed to mix, let alone mix a dog on purpose. I can't even imagine what they would look like as adults, and are you sure it's a mini and not a standard or giant schnauzer mix? That also wouldn't be healthy. Adopting is a great feeling and most of them are already tested if they are going to be good with children, cats, and dogs. Another plus is there already spayed and neutered, microchipped, and updated on all there shots.