I concurr, your new water was probably high in CO2, and aerating it for only 5 hours hours probably wasn't enough. I think they died from CO2 poisoning. IDK if testing your tap for CO2 would do any good, considering it could have been a one day thing. The temp spike also raised the CO2 levels, not letting it escape after the respiration of the angels.
I concur too. Other factors beside bacterial cycling will affect moved fish like pH, temperature, dissolved oxygen, CO2 content, and the presence of toxins like chlorine. It could have been the combination of these factors that stressed and killed your large angels.
