Your plant is way too small to sex. Also putting autos in the dark will do nothing to help you determine sex--that is photoperiod plants.
The number of leaves does not designate whether it is an indica or sativa dominant plant. The shapes of the leaves and the shape of the plant are determiners. Indica dominant plants grow short and squat with fatter leaves. Sativa dominant strains grow more lie a willow tree and the leaves are longer and skinnier.
Do not use pellet things you put into the soil. Do not just give fertilizers without knowing what is in them. The organic fertilizer for example, you said had all the nutrients you need, but since cannabis has different nutrient needs at different stages in its life, one fertilizer cannot contain what the plant needs for every stage of its life. So, when we ask what is in the fertilizer that you use, we are looking for the N-P-K numbers. In addition, you cannot mix organic and chemical fertilizers. The chemical fertilizers kill the microbes in the soil.
Growing tall is not necessarily good. What you want is close intermodal spacing--the space between the branches. This makes for more bud spots. It is not that autos do not produce bud, they do, just not as much and not as good as photoperiod plants.
You are going to need a lot more and better light to get the most of these. As a side note, CFLs are those curly bulbs that go into a regular socket. It sounds like you are probably using a T8 or a T12 tubes. I would get the light as close as possible without burning the plant.
You might want to do some more reading up ion the nutrients the plant needs. You can cause problems for your plant just giving it any old fertilizer you have sitting around. Cannabis has very specific wants and needs and the more YOU know about what those wants and needs are, the better yield you will have.
