Hey Thorax, dude your plants look hella good now. HSH4 is probably just showing weird traits (causing the marble spots and crinkle leaf). Some seedlings do this when they are still young, it'll probably grow out of it. But just to be sure, let us know if it is happening on every leaf or just a few.
Good call on the Kerala x Haze though, it does look a lil burned, and the nutrient lockout has started. Give it a good flush the next couple of times you water and back off on the nutrients (probably a 1/3 of the usual dose) the next time you do feed it. Also, double check the ph when you feed. Because having the ph off could affect the nutrient uptake which would cause toxic buildup of certain nutrients in the soil.
Oh, also... This method works for me, but it might not work for everybody. But, you don't have to re-pot every time you see roots reach the bottom of the container. If those are gallon pots they are in, then they can stay there until a bout a week or two before you flip to 12/12. I kinda like to get my plants a lil root bound before I re-pot them. I usually wait until the root systems drink so much water that they almost go bone dry if I don't water every 2 or 3 days. Only then, I'll be like, "Fuck... I really gotta transplant today". I use this method partially because I'm lazy, but also because it makes transplanting a lot easier for me. All the soil stays intact with the plant, so you won't have loose soil falling all over the place when you upgrade to bigger pots.