In need of help

Ok so this is my first indoor grow. BTW im a CA MMJ patient so its legal. I have 3 plants all started at the same time from bag seeds. All sprouted within a day or 2 of each other and all 3 are different strains. I have them under CFL's (3 to be exact) in a grow box that 2' x 3.5' x 4 and foil on the dull side around the inside walls. I do not have an exhaust fan but i do have an exhaust hole that closes and opens.

Ok so heres where my problem is one of the plants growth has been stunted so i have been keeping an eye on it. Idk what they are called but the 2 middle leaves that sprout through the middle, well this plant only has one. i kept it under the light and its still growing but extremely slow. I have no idea what this can be? should i just pull it? ive checked for bugs on all plants and i cant find anything.

Second one plant is turning a lime green. The leaves look healthy bu the tips are a lil curled down but they do not look unhealthy. All are receiving the same care but i cant understand the whats going on with these one, my third is looking beautiful and growing like its on roids lol. Gonna clone her when she gets bigger. Thanks in advance for any help.

You just gotta post pics for anyone to be able to help, hopefully clear ones.

the one with the burnt tips is from too much nutes different strains have different requirements and for the one leaf I would personally pluck it weed is dicotymous Wich means it always has 2 leaves single leaf plants are called monocots

Those first 2 middle leaves arn't leaves, there called cotyledens and eventually fall off so there no a big deal... Sounds like your probably overwatering them the way your explaining the leaf tips... We need pics to really help.....