In terms of corals, I would not remove any that appear to have died for at least a few months. I had a salinity issue a few months back with some major die off, and probably 25% of what I thought was completely dead has come back, but didn’t show signs of recovery until recently.
The amount of organics released by most coral die off will be pretty miniscule. You’re probably through the worst of it already.
Agree with above advice in terms of:
1) don’t raise temp back up too quickly
2) lots of carbon (toxins and organics)
3) lots of agitation in the display to oxygenate the water (and to get those organics foaming and over the top, so they can get down to your sump and skimmer!)
4) Keep changing water, few high volume changes >>> frequent low volume
5) Do get any dead critters out, but leave any corals in place as they might recover
Terrible loss. Hang in there and best of luck to you