There can be slight variations in size but if you refer to the NZKC breed standard, or go to your library and read up on them, it will give you some idea on what to expect.

No, white on the chest or any part of the body is deemed to be a fault.

Yes all my dogs are health tested. With hip and elbow scores. Eye, dental and bite certified by a vet. Similarly, any females my stud dog is used over must have the same credentials.

Contrary to popular belief, they don't eat a lot. An adult dog can eat between 1-2 kilos a day depending on what you are feeding. Be guided by your breeder.

Partly yes and partly no. As puppies and young adults their exercise should be restricted to running in the back yard to short walks then longer walks as the dog matures.

Everyone likes company and your dog does too. After all they are a companion dog. If you are fortunate enough to be at home, to toilet and feed puppy in the first few weeks is a real plus. You could always get another puppy?

It depends on you, your environment, your circumstances (do you have another dog) your personal and business life. Some will say females are better at guarding, because of their protective motherly instincts, also that they are cleaner than a male in their toileting habits. On the other side, males are larger and more foreboding to strangers.

Never leave a dog and a child unattended. Good breeders should put temperament first and foremost. A Rottweiler with a shy, nervous, or aggressive nature is like having a loaded gun. Stay away from dogs with poor temperaments. Try to meet both parents if possible and ask about the dogs temperaments behind the parents.