I'd have to watch their posturing to tell but it sounds like play. When we first got Teddy, he got beat up daily by Barney - he used to cry like he was being murdered. My dogs were older and it was a big disruption to have Teddy (who is really annoying) on the scene to disrupt them. It took a while but they are the best of buddies now.
As for the coat - different yorkies have different coats. Some yorkies have sparser coats due to allergies or poor breeding -like my Daisy
- and others have locks of pure silk - like my boys!