First, there is no reason to feel guilty for buying from a reputable breeder. I have 2 BYB Boxers, 1 Shelter GSD, 1 dumped Saint/Mal mix and a purebred cat from my mother's kennel. I am buying my next puppy within the next few months from a good breeder. no guilt here.
Second, a rescue is always a good way to go. Look for a reputable one that has the dogs in homes so they are properly evaluated. You can ask for one that is good with cats and small animals.
The more I learn...the less I know