Chuffy you're reading my mind -- even with the ear drumd damage there may be *some* residual hearing anyway -- and it will be a while before she can definitively tell because of the abuse.
Teaching a dog who has not a clue what "sound" is truly is *different* than teaching a dog who knew sound and WENT deaf. The first dog doesn't know there is this sense 'sound' -- all he knows is he feels left out. The second dog becomes and island in a different way -- he knew sound and knows what he's 'missing' -- it's a different type of fear/skittishness but the 2d dog knows there is such a thing as sound communication so you 'imitate' it.
For those who haven't a clue what we're talking about -- when a dog is born from certain coat (usually a "merle merle" combo) blends in sire/dam genetically there is about a 1 in 4 or 5 chance it will be a "lethal white" or albino -- in dogs, hearing matures later like sight does and at about the same time. But it is the pigment cells in the ears that complete the neural transmitters that make hearing 'happen' -- so a dog without 'pigment' in the ears will be deaf congenitally - they *have* eardrums, but the neural pathways were never completed so hearing never take place -- which is why everyone's looking for 'pigment' here.
Because of the abuse this dog has a lot of 'fear' BUT he's also got a strong playful side which will give her a place to start in gaining trust and confidence. Those tennis balls will be a powerful reward and she can play 'games' in hiding them that will develop the nose which is critical to teaching him to substitute sniffing for hearing so he knows something is coming up behind him and waking him up without trauma/fear.