I was able to extinguish most of his swingset barking with the help of my 9 yo. I held Kona on lead as she would sit still on the swing, then walk over to pet him. Back and forth until he figured out she was the same person whether she was on the swing or not. Then she swung gently a few times between "visits." Eventually she could swing several times and he would ignore her, lying in the grass and just looking around.
I take this as a good sign that this could be overcome so easily, but I can't do this for every contingency. He needs to develop more confidence. Hopefully as he grows more accustomed to his new home, that confidence will build.
A wubba is a Good Thing!