Our yorkie Gizmo is very quiet also. VERY active, but quiet. I think that's one reason the little furbutt gets in trouble so easily.

He's also our only pet right now and that might be one reason. He almost never barks, and when he does, there's a reason. For example, he doesn't bark at people or animals passing by the house, but he does bark if someone knocks at the back door. We haven't trained him not to bark or anything, I think it's just his nature.
He did try barking once to try to get us to feed him from the table, but a firm no and a loud noise (can with marbles) stopped it.
Unfortunately, I can't offer any insight about your other two issues. We don't have cats, and someone is home all day in our house.
Good luck with your research.
__________________
The fullness of our heart is expressed in our eyes, in our touch, in what we write, in what we say, in the way we walk, the way we receive, the way we need. -Mother Teresa (
RIP Gizmo 3/9/07-8/18/12)