I'm so sorry to hear of Zoe's passing. Our animals love us unconditionally and it breaks our hearts when they leave. I have three small dogs and a 16 wk old GSD. It has worked out very well. I rotate dogs out of their crates in the house. So when the three are out, the puppy is crated and when the puppy is out, the three are each in their crates. OK, I have a dog-house home decor... My focus is to keep the little ones safe and happy. I gradually introduced the puppy on a leash outside where the three have more room to maneuver. He is respectful of my little dogs and they get along, but i really supervise as I only want positive experiences for everyone. My three have "privileges" that the puppy doesn't have so they are satisfied. Go slow and have a management plan. Congratulations on your new baby!