To add another element of mystery to the situation, I see that the IMDb has added Bella Heathcote's name to the cast of the film BUT they don't list a character name for her. Though having no idea who's updating the IMDb listing, we have no way of knowing if that's a deliberate omission for some strange reason or if, like us, they're simply waiting for the matter to be cleared up.
I also noticed that IMDb is listing two new technical members on the film: Katterli Frauenfelder is the first assistant director and Andrew Bennett is the assistant art director.
Frauenfelder has previously worked with Burton on Alice in Wonderland, Sweeney Todd: The Demon Barber of Fleet Street, Charlie and the Chocolate Factory, and Big Fish, also co-producing the first three and working as an associate producer on the last. Frauenfelder will also co-produce DS.
The first assistant director tends to handle things like setting the shooting schedule, tracking daily progress against the schedule, preparing the daily call sheets, checking the arrivals of the cast and crew, maintaining order on the set, rehearsing the cast, and directing the extras.
Bennett has previously worked with Rick Heinrichs on Captain America: The First Avenger and The Wolfman as the draughtsman, which in general is someone who does the detailed drawings for a film's set design based on the production designer's concepts.
Being hired as the assistant art director for DS would seem to be a step up for Bennett because the responsibilities can entail doing research, accessing props, surveying locations, making models and helping to produce all the sets.