Do they look healthy

Start a diary............more info = better answers. Plant in pic 2 is burned from over feeding or salt build up in the substrate. All the plants are starting to "claw" from over feeding.............but without a diary and not knowing what you may or may not be doing, giving meaningful advice is almost impossible.

The set up looks nice but it need fine tuning even those clear drip lines will cause you problems with algae and nasties building up and feeding that to the plants, they should be black so no light can grow these things. To many plants, no run off and not possible to get in the tent to sort it, you need to do yourself a favour and keep it simple.. I have had all the systems you can get and nothing better than hand watering to understand what is happening.. you need a couple of big trays instead of loads of little 1s so run off can come to the front to extract. I could go on but of you sort these first it will help, I can't see this grow finishing with a joint out of it..

I'm wagering there;s no runoff based on the setup? Probably starting build up nutrients in substrate and exacerbating any imbalance of the fertilizer. This looks like coco? so, soilless with no runoff is not ideal. Basically taking one of the primary benefits of soilless/hydro and throwing it out the window. the 10% runoff maintains equilibrium of nutes. When you see a symptom it is never from buildup but rather simply providing too much, which makes diagnosis easier and more matter-of-fact. Despite a lot of the bullshit light specs peddle, the area of coverage for 18h and 12h are usually pretty solid. Over 18h, you'll want ~67% power while covering the suggested area and 100% over 12 hours. Apply some common sense if using different operating hours or area of coverage. IF deviating greatly from this (or proportionally so), the light could be part of the problem.

the plant in the 2nd pics looks to be having issues with PH. Can fix that up pretty easy. I don't think the light is to close. maybe it can be dimed a bit more but base this off of how close the inter node spacing is. to much space. more light. to little space, less light intensity. Most of them big lights are designed to hung 12-18" always with different dim settings to get the ideal photon distribution and avoid hot spots. Some of the plant looks a bit wilted like from over watering but I don't see it being a big problem might fix once the roots get bigger or just give em a bit less.

Healthy? No... To me it looks like there over watered, the feed system your using, does it only wet a small amout of medium, needs to completely wet then dry, this cycle is a must. If only wetting the middle the roots won't reach out or have anywhere to go and will struggle like what we are seeing here.. Hope this helps Good luck