not sure dude, looks kind of strange to me. It could be some sort of parasite or worm by the looks of it. my suggestion would be to cut those leaves if that's the only place they are!
there is no need for the rice as long as you have holes in the bottom of your pot. secondly if you plan on using fertilizer there is no need for the worms cause they will die!!!
flushing in my view is used better in hydroponics . in soil i would just water a little more than normal towards the end to flush some of those nutes out.
get grodon cubes , soak them in water for 24 hours. put one seed per cube. put in big zip lock, blow air in bag then close and put in closet( or dark place). when they sprout open bag and put in soil or hydro. temps need to be 75-85 deg. you dont need light on before they sprout.
if your going to do what ur saying, those are both male plants . Hemp is male cannabis . you have to have some females in the equation to get any kind of buds.
question one: Flowering begins when the plant begins to show it sex.
question two: tieing down is fine and won't hurt your plant, next time try to Lst (low stress training) its the process of trying down your plant the whole grow. Therefore making your plant low and get more yield.