Renee i am also a coco grower. I only give 1/8 strength roughly of nutes...i use GoBox nutrients from General Organics. Like the rest of the guys and gals up top said...just go easy on the nutes. Ive had two feedings in 4 weeks. Only because about half way down the grow medium i added top shelf fertilizer and that holds moisture well. Autos tend to get funky coloration on their leaves from the nutrients and as a coco grower all you need to do is within a couple days of noticing any spots or burns, run water without nutes through your medium. That will help your root base feed at a different rate. They wont be soaking up a concentrated amount of nutrients at once. But dont stress...my first grow with autos i worried about each and every thing that i noticed on the plants lol so just dont let it get passed nitro burn marks which is just the tips starting to turn yellow and then it works its way up leaves, burning a path towards the stems...thats what to watch out for. Just dilute your feed mix and always under feed if you anything. Autos are tough but will take a beating if given to much to fast. But since your growing in coco youll have great runoff to check your ph balance. Im not really seeing anything on those guys you posted pics of that would be a threat. But could be missing something. With enough TLC they will be big and bushy in no time
Good luck my friend and feel free to PM me if you have anymore questions regarding the grow or with coco/peat moss.
Sorry for the book...lol happy smoking Renee!