Requirement: Requirement is the cost to obtain this SC for other people, if its custom. Because upon making a custom SC, you've indirectly agreed to a copy being added to the universal SC database.
Range: Range is what the SC effects. If it's a physical SC, they most likely only effect you. But for people with lets say, Sensory, it would state how far you can sense.
No you don't have to learn the SC you put into your app. But any SC you wish to obtain after your character is approved needs to be learned IC.
Also, the extra SC is for those who decided to not have a clan or Bloodline, thus that answer would be no.
And since Chunin are of B grade, your SC can only be of B-ranked or below.
Now those question are answered, I welcome you to the site and stop stalking me, it's scary.
~Anubis | The Bishop | Éowyn