First off, only post one thread and in one area, not three. It helps to keep the place, and your feedback, organized. Thank you.
What you are seeing are called cotyledons, they are a set of 'false leaves' that come out of the seed at first. In a day or two you'll see the first leaf set emerging from in between the two cotyledons.
Just make sure not to over water, I always had trouble with overwatering in rockwool when they were that young!
Is that what you were asking about? Or the cotyledon tips? How far away and what kind are your lights? I usually keep mine under fairly weak light till around second set of leaves then slowly intensify it.
Happy growing!