Unless I'm really surprised by this project, I expect it will be a waste of talent to hire Debose to play Calypso. At worst, it's going to risk some bad 1950s racial "voodoo" tropes. I'd rather see her playing someone else entirely.
For all we know, they might be aware of that and could well do something else with her. We'll have to wait and see, though I understand your skepticism.