They look like they can revive - although the one 10th from the top and 9th from the bottom (uploaded twice) isn't obviously alive from that photo. I let my M. prolifera soak for a day in sterile water, planted it in sterile sand and kept it at least damp until I saw signs of growth. Then I moved it to a pot with "cactus mix", and treated it with my usual benign neglect that cacti seem to love.
