The Miniature Schnauzer is classified as a terrier while as the Standard Schnauzer and the Giant Schnauzer are classified as working dogs.

No, there are 3 types of schnauzers. Miniature, Standard, and Giant. They all vary in size.

NO

No. Giant Schnauzers and Miniature Schnauzers are not the same breed. Giant Schnauzers and Miniature Schnauzers have a common ancestry in that both breeds were "bred-up" and bred-down" from the standard schnauzer. The Miniature Schnauzer was "bred-down" by breeding terriers with the larger Standard Schnauzer. The Miniature Schnauzer is a terrier breed. The Giant Schnauzer is the result of breeding larger breeds, e.g. the Bouvier des Flandres and the Great Dane, with the Standard Schnauzer. The Giant Schnauzer is a Working Dog breed. Other than appearance, the Schnauzer name and their common ancestor, which seems like a lot, the Miniature Schnauzer and Giant Schnauzer share little else.

You could try to breed a giant with a mini but it probably depends on their first impression and if the miniature is intimidated by the giant. Also, prob depends on the gender, and which is which.