
Hi Jill,
It sounds like you're doing the right things, and I'm certain you did the introduction right, showing from the outset that Barney was favoured, so please don't worry about that.
The classes sound good too.
With her ears going back and her tail dropping it
sounds as though she is fearful, rather than dominant-aggressive, though of course it is impossible to be certain without seeing her. You all sound sensible people - if you can reward her
before she starts reacting to other dogs, you may well see some benefits. The ideal scenario is where she sees another dog and associates it with looking to you for a treat, rather than trying to get drive the dog away. Other dog = nice treat! Timing though, is critical.
I sincerely wish you luck - you sound like good people who can turn this dog around.
:)