First the plant uses the leaves as a way to control the internal temperature of the plant so they do play an important roll. You can tuck them out of the way and tie them up.

Not question 2, you could be facing a damping off problem. The roots are small; plants don't grow as fast or as big. Sometime there are red streaks in leave stems and in the main stock. Do they leaves have yellow blotches.

What Ph are you running? About how old are they and what cycle are they in?

See of green is a bunch of plants in a very small area you grow them short and flower early only harvesting 1oz to 1.5 ounce per plant. You make weight by having volume.