Trouble in Paradise

Okay, so this gets a little complicated down the line. But I feel the need to write this as it happened last night.
-For reference, Jack is my male, the biggest. Boo is my medium female, missing two back legs. Bubbles is my small female. All are generally the same size but I can tell the difference.-
 The water side was a flop, about 24+ hours after the water was put in, there was an inch drop in waterline and it went into the sand. I had to do what I could to drain it and lay stone so they could walk around.

  On to the point of this post... Last night I am on my way to bed, and i hear a loud strange clicking. Now these crabs make noises, you hear their legs walking on hard things, you hear them digging and scraping or snapping their claws, but they also click. This was not a normal click. So I looked in and saw Jack laying awkwardly on the sand. legs in normal curved matter, but tilted flat. Mouth and front laying flat. He was the one clicking so strange.
Now I was worried, then I turn on the light and theres little to no orange color to him. I immediately think of the caulk, did some of the chemicals seep into the water that got into his sand?! They wet their gills with puddled water in the sand sometimes. Oh no!! I gently scooted him onto a piece of paper, and transferred him to a lidded container with a hide. I sprayed him with water to moisten the container and him and watched him go more and more limp, and heard the clicking slow and then stop. Did I kill him!? I had to get the others out (if the sand was poisoned they soon would be too!)
 So I start digging and find... a bright red orange crab.. Jack? Jacks the only one with red orange. Bubbles is the only other one with all legs... but this ones so big and shiny and with a soft shell, Bubbles must have molted! Transferred the REAL Jack to a separate container, rocks, dish of water, hide, misted. Hes fine.
 So I dig for my third... and find a tiny crab. Bubbles?! Boo was never that teeny. Oh my word I am a bad crab mommy who cant tell her crabs apart. In truth and reality it was BOO who was dying next to me... with all her legs? She must have molted... Sure enough after all crabs were in their containers, i found her entire old shell. =( What have I done?
  -You are not to handle a crab after molting. Molting is stressful to the animal and commonly makes them extremely lethargic until their insides expand and their shell hardens. Handling during molting may cause death-  and I handled her... and I moved her!
  Currently. They are all still in separate containers, not ideal size or substrate. Not ideal at all. But I have no more sand and am not moving Boo. Boo is still appearing dead. her eyes are mostly sunken in, still not moving. I feel terrible. Like a horrible person, I should never have touched them but I still fear the sand may be toxic and dont want to risk that. I dont dare touch Boo for a couple days to a week, to be sure she is dead or to be sure she is alive and regaining strength. It can take them time to strengthen. Until then I wont bother her. just look in through the side. This is what the molt looks like: