Iffy temperament because you said that she was "timid" and cautious.
Rottweilers should not be timid.
It sounds like you love your dogs, please have her spayed and the male neutered so that you do not have an accidental litter. Her pug nose and his long nose....right away should take them out of being considered for any thoughts of breeding.
To breed, and to be a good breeder both the sire and the dam should be shown...so that they fit the standard for the breed. They should also have titles, some sort of obedience or working titles, so that you know they have the temperament and brains and are worthy of breeding. They should also have their hips, elbows, eyes and heart all certified by OFA. Go to their website so that you know what this consists of.
Orthopedic Foundation for Animals The testing can only be done at the age of 2 or later. If you do not do any of these things you will be a BYB...and you may produce poor quality, unhealthy pups.
This is a breed that is riddled with health problems...hip dysplasia, heart problems, cancers, elbow dysplasia,etc. Only the best should be bred to the best. Very hard to find good puppy homes....so many BYB puppies end up in shelters or passed down to other people.
Good breeders will take their puppy back at any age.
Breeding takes years of experience, and understanding pedigrees and knowing what the breed standard is. Takes much more then having dogs with a penis and a uterus.
Gina