Samson has the yappy bark when he hears someone at the front door or a strange noice in the house (yesterday he was growling at the thunder, we live in AZ and hardly get any rain where I live so this was a new noice
).
I would say he isn't the sterotype yorkie when it comes to barking.
Harley is very young, only 11 weeks old so I don't think he has found his voice yet. When he does I believe he will be the yappy dog. He is already very vocal when he plays, sleeps, walking around the house. He just makes these sad whinning noices or is expressive when he plays.