actually, from personal experience... I've found that when the shell of the seed is still connected to the plant, its best left alone.. and left in the dark. Only for a day or two.. and if the plant still hasn't gotten rid of the shell on its own (which sometimes the shell can get stuck).. then, what I do.. is I gently remove the shell with a pair of tweezers. But please, if you try this yourself, which, I wouldn't suggest for a first time grower... you must be very very gentle and you don't have to pull hard.. be very very gentle if you decide to remove the shell yourself.
But again, usually the plant will do this on its own.. when its good and ready.
Patience patience patience!! is key when growing cannabis... let the plant do what it wants to do. Its best to let the plant do it on its own.
Hope this helped.
Also, for the lighting question, you should wait to give your plants any light, until the plant is standing straight upwards.. and the stipules that the plant has when it sprouts.. are there to protect the plants first set of leafs.. and will open up when its ready.. and by this time.. the 'shepherds hook' that the plant first has when it first comes outa the soil, will straighten up on its own. It is this time, when the plant will be ready for light.
That's what I do.. I wait until the plant has straightened itself out.. and the stipules have unfolded before giving my new sprouts light.. but.. you can give them light before this happens.. I'm just explaining what I do personally.
Either way, good luck my friend.