Morning brother, overall the plants look great..nice shade of green,no big issues with nutrients or deficiencies I'm seeing,especially in the new pic..
1.The nice,good solid dose of jacks+epsom SHOULD clear whatever nitrogen/mag deficiency you had..it will take a few days for the plants to respond as the roots uptake the nutrients and the plants assimilate them.. I'm not too clear on coco loco soil..obviosly it has coco but at what ratio..i dont know
2. Your smart to be wary in burning the plants..what kind of nutrients and PPM are you feeding with...what ph?...what is the ppm os tap water?....but again,those look amazing,a small nitrogen deficiency never killed anything
3. Burnt tips can mean several different things..so please take a picture if its bothering you so we can diagnose..it can be everything from a deficiency to overfeeding to lightn stress..so pics and more details so we can help you.they look beautiful though man