Little dogs to be are a lot more like people. If you like having a DOG dog..then they might not be for you. But if you want a dog that's very similar to a baby or a small child, then go for it! You'll have to puppy proof your house (wires, small objects they can swallow..like a baby), be very careful about where you step. Even if your bigger dogs are friendly, if they are rambuncious they could easily hurt a smaller dog in playing. You also have to worry more about them getting easily stressed cause their blood sugar level can drop or they can get dehydrated from diarrhea. They need a lot of attention, so if you have a very busy lifestyle, they might not be right for you! Good luck and I applaud you for doing your research instead of just giving in to that little yorkie face!
