Welcome to YT, this is a great place to get good advise. I have a 5.4 lb yorkie (Bella) and 80 lb black lab (Lucee). Lucee is soo gentle and so good with Bella but I still will not leave them to play unsupervised. Sometimes when they play they BOTH get too excited and I have to step in because I'm afraid Bella will get hurt. It would be an accident but it could happen and I'm not willing to take the risk. I would not recommend leaving them alone unsupervised. Bella is my first Yorkie too, I've always had Labs. She is such a treasure, she's defintely stolen my heart. Enjoy your new baby!
And I thank you and your family for your service to this great country and for the sacrifices that I know you all make. We really do appreciate it and it's an honor to be able to give you my little bit of advise