Hi there and welcome! It sounds like you're doing everything right with the fish oils and the probiotic. My youngest also had mange because of allergies, and all it took was to change him to a raw diet. He was allergic to was his food, which is a huge thing I guess. lol.
Audrey looks so sweet, and seems like a big cuddlebug. All of us bulldoggers here would never have given her back too. So glad she found you two loveydoveys.
Oh, and she sooo has the bulldoggy traits to me.