FWIW on the yellowing, I'm going thru a similar thing right now -- having a plant in soil I thought would carry it for awhile, but it's showing up with a pretty clear N deficiency. I gave her a 30-10-10 feed at 1/2 strength, I swore she started to improve, and then went back to yellowing. All this is happening under a similar set of conditions that nute-burned the shit out of my last grow.
I'm leaning toward the side that MJ strains are highly variable in nute demand / tolerance. What you have does look like pretty straight N deficiency to me.