The yeast should be fine; a lot of vials and smackpacks have suffered much greater indignities during shipping than yours did during the power outage. I've bottle-harvested yeast that was shipped from Belgium to Texas under what I assume were not ideal conditions. If you feed your yeast, you should get a floating krausen of live cells. You can skim that off and use it as the basis of a "clean" starter free of dead yeast.
Say no to intolerance: love gluten and lactose.