Little growth

As mentioned in the diary. A mix of too little light, too much fertilizer, and too much water. I'm still not so sure about the fertilizer, but definitely light and water. I agree with massivetids. Start over from the beginning. If you really want to keep her, give her light first (35cm @ 25-30%) and let her dry out. Then only give enough water so that she is completely dry again after 3-4 days. Once she has grown bigger and her roots have developed well, water the whole pot so that a little water drains out at the bottom.

The problem here is overwatering. You can better start inside a small cup like a plastic drinking cup with a few holes in the bottom. Some people recommend to start an autoflower inside the large final pot but this does give more problems (mainly overwatering) then when you repot them at the right moment. The right moment for repotting is from the moment the first root sticks out of one of the holes. The plastic cup is really easy to remove and you gently repot them inside the larger final pot for the rest of the time till harvest. I am sorry to bring you the bad news but these plants will not grow anymore and you need to start over again.

It looks like you're feeding them a stupid amount of nutrients. First thing I would do is drastically cut back on feeding until you understand the nutrient needs of the plant. Seedlings don't need any nutrients at all for the first few weeks. 1. Is your coco mix pre-amended with nutrients? 2. Is your PH in the correct range? Are you measuring your PH before or after you mix your nutrients? 3. Your diary says your light is 100 inches away from the plant. Depending on your model, it should be anywhere from 16-30 inches away. 4. Are you overwatering? Let the coco dry out a little bit before watering again. Seeing as your plants are auto's, they might bounce back but don't expect a good yield. You may get just one cola worth of bud. Good luck friend.

Low your PH and give less water, before watering it let the soil dry out Peace :D