what seems to be the problem with these plants? la...

There is a pallet of issues with all of them. Maybe right bottom looks best and generally looks just hungry All troubles starts either from bad watering regime, when water is applied while pots were still wet and heavy. That could lead to oxygen reduce in root zone, slower nutrition uptake and buffering your pH off Two things, wet/dry/wet/dry cycle and pH will lead you to good harvests in soil, even without nutes. In Coco you would need to add food heavily, but first two things always goes first You are far in flowering, leaves won't become magically better, they will only get worse. Pure pH water and dechlorination before phing it is a must for you now. Two full cycles wet/dry without food. Then you can return to you feed regime with first few feeds only 50% of power adviced by manufacturer or your plan. I think all food is still in the pot . pH SORT IT ! THATS ESSENTIAL.