Bring the dogs together on neutral ground and let them meet with loose leashes. Watch for reactivity and reward good behavior with praise.
Don't get mad if your dogs don't get along. Use baby gates to keep them apart, and if that doesn't work, talk to a vet behaviorist.
Walk both dogs, watch how they interact, put their food bowls in different places, watch their body language, and give them choices to build trust.
Cats and dogs can be friends, but the introduction must be gradual: never force, don't invade space, and don't chase/bother during feeding. Cat determines when and how to interact.
Introduce baby's scent to dog before meeting and give treats to create a positive association. Let the dog out. Walk dog, enrich, and monitor behavior.
Adding a puppy or kitten to hshld? Supervise introductions, separate for part of the day, and don't leave mature pets alone; they can be hurt by larger pets.
New pets should never be left alone with children. Choose a pet that fits your lifestyle and teach kids how to act. Certified animal behavior consultants can help.