Joy started doing extra work because one of her co-op teachers who was also her theater director (and is a family friend) also does a fair amount of extra work. Rosemary had several background scenes in the movie "42" and has been in Dance Moms as an extra "mom", for example. But she's always been more of a behind the camera type of person and she doesn't take being yelled at by directors very well.
I think she not only inherited her dad's mimicry ability, she has taken it a few levels up. And voice acting is something she can to without lots of other people around - or uncomfortable situation (like being made to walk behind a moving school bus for hours in a yet to be released movie).
Yeah - same director.....
Anyway, thanks y'all. If you think about it, watch the episode on ABC's web site and if you see a red pill box hat floating around, it will be my daughter!