Sorry to hear about your loss. I hope the others make it. I just got some Azuls myself and have been overly concerned since its my first group of cichla.
No idea there is a post on here that everyone has them at 86 to 88 so i thought mine was too low but im guessing thats what did him in. I think those high temps stress them out. So i brought my water back down to 81.
Same thing happened to my kelberi I have 40+ in 180 tank and 10 died, symptom: breathing fast, dying slowing, no external sign of sickness, think of bloat. One I did was over feeding them, ammonia level was a bit high.
Treat: add oxygen ( air. Pump) salt, water change, if possible remove them into a new cycled tank.