Afternoon here in Oregon, sorry your little gals are not happy. I see a few issues not sure why some growers are not filling up the grow bags with soil less room now for roots, been seeing this on a few grows? I do not grow in straight coco an perilite i mix it with my composted soil i make along with wormcasings. I saw where you said you did a double feed perhaps they were too young to handle it? I myself use a simple nutients for my plants so i don't feed bloom till i see budlets cause the soil i use is enriched and autos unless your familiar with them don't like heavy doses when young.
If they were mine i would do this....take the whole pot to a sink and run a slow gallon of water only threw them really soak and drain that out, let them rest dim the light if it has one, give them a rest from the lamp for several hours. How's the temps now?