i think your confused by to many recomendations,everyone grows difrent,so 50 difrent ideas,find you someone you think know there shit and try it there way at least til your plants turn around ,i read this whole thread and im thinking the biggest problem you got is over thinking it,transplanting isnt the answer,i think you need to get the knats under control and leave the plant right like it is,you never did throw up another pic yesterday.
so i cant tell what you got,the first pic is saveable with tlc,but from all the difrent ideas isnt gonna be,pro mix is by no means a set it and forget it medium either,ocean forest either,but ocean forest has all the goodies the plant not only wants but needs,the age old statement of its to hot,most that say tis read it,i run seed to harvest in it,if it to hot it from dumping nutrients in it before the nutes already in it were depleted,so thats a load of crap.
like i mentioned yesterday and from the picture i see ,the only one,that plant can be dug up with a spoon and transplanted into a solo cup,were it doesnt get over watered and such things like this happening,but i cant really say,havent seen it.
far as the light statment with back if hands ,works like a charm for HID lighting,but led lights is another ball game,so that what i mean difrent methods,i still think a fresh bag of ocean forest ,i mean pick that bag up and if it is light and hasnt been rained on ,buy it transplant your baby into it,and we go from there,from there will be water only,