With that many questions you should have started your own thread.

I'm a noob too but, you should never use nutes with seedlings. And you didn't need to repot for a while. If you repot too soon it can be harsh on your seedlings. Also your plant looks like it might be starting to stretch a little so I would get your lights a little closer if it is possible. And finally I wouldn't use Miracle Grow if I was you. All of the people that have tons of experience say NEVER to use M/G.

Also, just for future reference... I know that you are new to this forum by the 1 post.. But you shouldn't squat on someone elses thread. I don't really care but some other people at this forum would get pretty pissed at that.

I hope my advice helped you out some. Keep doing research though. Good luck.