from reading your troubleshooting forum, the only thing I can think of that may cause that curling is humidity issues (since you have no idea what it is) or it may be the FFOF soil that is too harsh for the seedlings as of now. I'm sure the curling leaves will subside in the following week or so! I hope they pull through for ya!!!!

One of your pictures it shows your lights....They don't look like 2700K to me. Maybe the flash of the camera caused it to have the "white" color to it? IDK maybe you should lift the lights a bit to around 2-3 inches rather than 1-1 1/2
and see if that makes a difference!