tossing sump is good idea. I understand you need to get the fish back into the tank, but if you are adding all new water? I'm still rather new at all this, but I think your tank will go through an inevitable cycle and the fish may suffer. Maybe someone can take the fish in for you until this is complete?????
You want WHITE DISTILLED VINEGAR. just keep rinsing until you can't smell it anymore. If some is left behind, it will not hurt anything especially in a large tank.
If the water in the tote is stable and the fish seem okay, chances are good that the rock is okay. Because rock is porous, some things can get trapped inside...
This is a tough situation for sure, and I don't envy what you are going through.
These are only my humble observations...hopefully a veteran reefer will step in to confirm.
Good luck Mike.