JRTs shouldn't be loud. In a house that currently has a bc, whippets and a couple of cockers.. the JRTs are not the loudest! Nor the most frequent barkers.
A confident dog is not a loud dog, and JRTs should be confident.
Not barking at runners is good! I would keep treats on hand. Kat when she was young was a bit of a barker (at everything, hers is over stimulation/excitement while on leash. She wanted to visit everyone and everything) I just rewarded her frequently for focusing on me. So every time she barked I distracted her by asking her to sit, hand touch, etc and the rewarded her. I kept her attention on me so she couldn't get over stimulated.