Looks a little like overwatering and possible root problems to me. My guess is those pots don't have enough drainage and so the roots are not getting enough oxygen, and too much water. Sorry to be a downer, but all your pics look like imminent root trouble to me.
I bought some of that Kellogg soil last year, it was terrible, frankly. Very woody, not enough compost, I ended up amending the shit out of it and cooking it for 6 months before finally mixing it with some other soil to make it usable.
I really enjoyed growing in Royal Gold's Tupur coco, and I heard their King's Mix is even better. If you decide to rock coco I would recommend those products over all the other coco mixes on the market. I decided to run Roots Organics 707 this time, I like variety.