it might help it finish quicker in the end, but for now it'd probably slow it down. They need as much light as they can get for growth. If it's a sativa dom plant you aren't even half way done and shouldn't see anything but nice white hairs.
A plant needs leaves for photosynthesis, a branch that has a fan leaf will get bigger than a branch without. I also see the fans as food storage. If something goes wrong (bad PH, missed watering) and the leaves start to yellow it's because they start to use what is in those leaves. As was...
no not really, he played football on both sides of the ball and baseball from high school until he was in his 40s. Not outrunning people but running them over.
If you haven't fed them, but then again it sounds like you're not the only one doing so..:neutral: it's very unlikely that they have nute burn. What kind of soil are you using? Most soils, unless they have time release nutes in them, only have enough fert to feed a plant for the first 3 maybe 4...