Idk much about those lights but I have a cheap one I use and have to keep it up quite high or else my seedlings look like that they don’t need much light at that point I usually let mine stretch up just a little bit into it so she tells me she’s comfortable with the light level
Looks a little hungry to me I use hydro so not sure on organic nitrogen solutions i think you can use diluted urine haha but I’m sure there’s a less messy way
Can’t see the pic very well on my phone but IMO I would only ever cut a leaf off in flower if it was directly over a bud even then I’d try bend it out of the way first
If you start with around .33 ec water you shouldn’t have much problems with ph I never adjusted the ph for any of my coco grows I’ve just started doing dwc
A light mix of nutes will be a good start now I personally always feed at least a quarter feed with canna even before the seed pops. I use a 400w led and I have to keep it at the very top of my tent I think you could get that one quite close until it stops stretching I wouldn’t go too close...