I'd also make and have ready about 20g or more of new SW
to do a water change.
I'd remove the water from the main far enuf down to keep the rocks covered. That water you removed could be in a new tupperware container (hopefully, large enuf to hold that water and rocks - 20-30g maybe) you put to the side while you 'scape with the others. As far as the shrimps go, you can put them in the same tub IMO
. As you remove rock, the shrimp WILL let go and drop of into the tank. Remove what crabs you can, otherwise, they'll stay on the rock and return with the rock, no big deal IMO
Depends on the extent of you re-'scaping as to how many empty tubs, buckets, or otherwise vessels you'll need. But have new water ready to go. I also wouldn't worry about the corals. Just put them in the vessel of your choosing in the main water you removed.
Also, I'd say if you're gonna work for an extended time - say 1/2 hour or more (just my opinion here) I'd air an airstone or a powerhead to the vessel(s) to keep oxygen up.
One other thing - if you ever think you want sand burrowing critters (gobies, pistol shrimp),
make sure the rock you re'scape is pushed down into the sand onto the bottom of the tank to keep those critters from toppling the rock when they dig.
On a 72g tank, I'd try to remove about 15g or so for my holding vessels. As I replace'd the inhabitants, I'd replace the 15g removed with new water. Then, you've just done a 20% water change. Anyway, that's what I'd do.