I'm sure it's been mentioned, but there's no such thing as a "miniature" yorkie...there is the Yorkie. That's it. They can be 7 lbs and under to fit into the standard, but MANY people have just as adorable yorkies that are bigger. When I bought my Joey, I was very naive and believed the people when they told me I was buying a "miniature" yorkie...I also believed that he wasn't from a puppy mill - yes, he's a pet store dog.  
Joey weighs 5 lbs, and Tank weighs just under 4 lbs. They often play with labs, australian shepherds, other little dogs, and children ranging in age from 2 to 12. Honestly, they're fragile pups, but they know when they need to cool it with other dogs. My boys will jump up onto a couch or something when they've had enough...I wouldn't ever leave the bigger dogs around smaller ones, but as long as you're supervising, I see no issue with having both...        |