Hi and welcome to YT
. Glad you found us. And bless your very big heart for taking in rescues and for working at the shelter.
I don't have much advice except something to try for the barking...take an empty metal can and fill it w/ coins or nails. When he barks excessively, shake it super hard and say NO! -- the goal is to startle him out of his barking / interrupt him. This doesn't work for all dogs, but it might help.
As far as your other needs, I'm rather useless...but if I were you, I wouldn't hesitate taking him to a class, despite his issues...a good trainer *does* understand these kinds of issues and should be able to help, even in a class. And if they can't help, they could give you your money back and perhaps recommend someone who could.