I am so sorry for your loss - an idea for using fans is to place a pan of ice in front of a fan so that the air is cooled as it is being circulated.
We live in northern Nevada where temps can get above 100 degrees in the summer but we have really low humidity &, while it is hot, it is more tolerable than the high temps with humidity. I remember as a kid growing up in Louisiana trying to lay in the sun on a lounge chair in the backyard on the grass & not being able to tolerate it because of the moist heat coming up from the ground. It was just too hot and hard to breathe. You said the chicks and hen you lost were on the grass, I believe.
I am glad that you have a place to put your other chickens until the heat passes.
I feel bad for you children, too, especially the one that helps you with the chickens.