I love the second picture!! Mid-flight!
I have 5 dogs from 4lbs to 40lbs and they all play well together. Well the oldest doesn't actually play...
The bigger dogs seem to instinctively know to be gentle with the smaller ones. They're the same with small children, too.
BTW- Villette has a beautiful black cocker (I think she used to have 2 ?) so she can probably give you tips on how they get along with Yorkies.