stick your finger in that soil, is it moist? If not give it a nice watering, then wait a few days and check again.
shut off the HLG 650 and put them all under the 200w LED for now to save power. When they get bigger you can turn the second light on or whatever.
Don't feed them, the happy frog has enough nutes in it.
wierd to mix coco and soil but it should work. Coco is hydro medium and happy frog is soil so I'm not sure how you'd want to pH but the coco could be stripping all the cal-mag from the soil if you didn't charge it. You may want to add a small amount of cal-mag once and a while.
download a lux app on your phone or buy a 20$ lux meter, or check the manufacturers recommended specs for distancing that light. Either 8-15k lux from the light to the canopy will make sure it isn't too much light , or take the recommended veg distance and add a little to that and let them thrive
I'd guess you are giving them too much light, but the soil also looks a little dry. Too moist or too dry of soil can cause issues but the mix you are using it is hard to over water. What size pots are these in?