My plant looking a bit ill?

Hello, Im a first time grower and have read most of the growing topics in this thread. Okay, so ive got two babies here, the two of them have now sprouted and one is about 1 cem tall and the other about 2 inches....(i was thinking a bit stretchy, so i did move the light as close as possible), the others just started to like the light . The problem is that the one that is about 2 inch tall, the little leaves on the top are closed together not spread apart like they where last night, well one is way bigger than the other...the other looks a bit brownish on the underside(the side you can see) could this be to do with the light isnt strong enough? They are only about 3-4 days old. However there are two new leaves forming on the bigger one. I dont know what strain they are, and i know theres no way of telling, just got them out of a bag of skunk i bought.
Im using Flouro Lighting (sun-Glo flouro tubes), keeping the light approx 2 to 3cm above the plants. They are in high quality compost soil too if thats any help.

Here are my other quick questions:

Q: How many of these lights should i have for growing 2 plants ( dont want them very large, just enough bud to smoke to test).

Q: How long will it be (approx) till my plant has distinguished MJ leaves?

Q: Are there any early warning signs i should be looking for? And i know this shounds stupid, but how can you tell if it actually is a Cannabis plant? I could have been given some random plant seeds..

Q: good or bad on the first two leave i talked about?

Heres the flouro tube info:
Sun-Glo (by Hagen)
Light spectrum Emitted: 4,200
LUX: 40

Heres a pic of the seedling (its a bit bigger now,but you get the picture):
http://i6.tinypic.com/1zh1jyx.jpg