However, my impression of the epoxy health hazard is that it is uncured epoxy that poses the greatest risk. Particularly, it is unreacted hardener that is the most dangerous. Some people can be sensitized by fumes, most only by actual skin contact.

By the time you are sanding the epoxy should have hardened. There should be no more risk of sensitization from hardened epoxy dust than there is from touching a finished boat. You will still need to address dust issue, but this can be handled like any other dust, with a collection system and good ventilation. Just don't ignore the fume issue . . . ventilate . . . ventilate . . . ventilate.