1: Kacie is like that, she goes out in the morning and does her "lassie" barks as she patrols the property.
She barks when she scents something(like right now!) and barks when people pass by the house. She isn't real friendly to other dogs if they are posing a threat, but is ok if they are neutral. Confidence isn't the highest, so wants to make threat go away with a show of noise. It isn't really a dominant behavior, but more of a warning.
2: Pushy bark. Confident dog with no reason to sound off, unless there IS a reason for making noise!
3: Higher threshold, probably not real confident, but not really timid either and wants to remain in the background, let the others take care of the world. Does #3 have very high drive(food, prey or pack/I would assume not so much)?
Just my take on it, curious to hear other opinions!