https://www.rollitup.org/marijuana-plant-problems/37149-plant-dying.html for a little while u will need more light and paitence just let it grow in the new containers you will be getting with out all the fertilizer and only water when its dry about 2 inches down.
what do u mean by strain? indica? sativa? i have grown seeds from some fair to poor bag seed and have had great results also have grown some known good genetics and had a bad plant so idk
yea their too small to be fed they dont need to be fed for at least a couple of weeks and the time release stuff u have will kill those seedlings for sure! but it is entirely up to u