this is alot of info to comprehend if this your first grow but i can tell you that you will definitely need a larger space & usually the 2 main causes of leafs looking burnt is nutrients either to much or not enough & the light if its touching the plant. by the way I spray my plants everyday with a squirt bottle full of water - keep that up cause that will not cause your leafs to burn up & its good for plants. your bottoms leafs once your plants get 6 inches might start to turn yellow - these leafs that are turning yellow are usually your fan leafs which eventually die off because of lack of light hitting the bottom which is ok and nothing to worry about