Gosh...im sorry for your lost. Its the hot season now and temperatures can go up by quite abit. Do you have alot of pumps/powerheads running in your sump/tank? All these gives out heat which will raise your tank temperature.
Hrmz, for your temporary fish housing containers, make sure you have an air stone running to provide some form of circulation within the container. As for changing anything, i guess you shouldn't panic so much, how big is your tank? And if you have a powerful skimmer, the "pollutants" released by your melted corals wouldn't caused much of a problem. Still, a partial water change wouldn't do any harm. If you are worried, do a bigger one.
Hrmz....things like that happens and there were a few times i wanted to give up too. But im sure the hobby has given you alot of joy for the past 3 years and to give up because of a crash after you've accumulated all the experience is a waste. Get your chiller repaired and since your tank is fishless and has no corals, why not take a chance to do a rescape...after you get your chiller running again, it'll look like a new tank! Good luck!
Oh, just came to my mind...maybe we should all standby fans to cool the water if the chiller fails.