An entire crew missing with their belongings undisturbed seems like may have been an insurance scheme or something, but I've also seen wilder theories like alcohol fumes driving people mad
I answered the same question here 18 months ago. Sadly things move pretty slowly in the world of Mary Celeste studies, so I think that response may still be of interest to you while you wait for fresh answers to your query:
Is there any sort of modern historical consensus on the fate of the crew of the Mary Celeste?