Its most likely normal for the plants to lose some leaves during flowering. However i dont know the strain so i cant say for sure if its normal..Most cannabis plants do lose a good amount of leaves towards the end of flowering..

You can move the roots away from the inlet and outlet and they should be fine. But ONLY if you do not touch them with your hands..Use something that is very sterilized..You can shock them so be VERY careful and do it slowly...The inlet and outlet on a dro system is the most important part, you should have put a little piece of screen over both holes..