Question about IPad Mini Swap

Yesterday I have discovered a crack on my screen, on my IPad Mini. It's not a crack that looks like the screen became a puzzle, it's more like a crack as thin as a hair, and not even that long. It even looks invisible that you wouldn't even know it was there even when it's on, unless you look for it. I got my Mini on first release at Apple.com and had it shipped to me, and i have kept it in the Otterbox case since. Just yesterday, I was using my IPad and I discovered the crack on the bottom left of it. I thought it was the screen protector on the case itself that had the scratch, but when I removed the case, I found out it was a crack.I don't even know how long it has been there. I have called the Apple store this morning, and they said they can swap it for a new one. I would like some information about this. What I know so far is that it's almost like exchanging merchandise, by getting something of less or equal value. The questions I have are the following.

1.Do i pay a difference?

2.For what amount will they take my IPad for in the condition it is in? (as an estimate.)

3.What needs to be brought in? (recipts, cords, power outlet,box?)

4.Does the battery have to be a certain percentage the day I go?

5.Will it be possible to use a student discount if i have to pay a difference? (I am in college currently)

6.Can it be swapped with another capacity IPad Mini? (Just curious)

The condition that its in in near perfect. No heavy or extremely noticeable scratches on the screen and nothing on the aluminum backing. All there is just a small scuff on the bottom right bezel which came from a small drop (when I diddn't have the case.), and the crack on the bottom left. The crack did not come from the drop, because that happened two days after it arrived at my house in November, and it would have gotten much worse if it was since then. Pictures will be included. And just in case I live in NJ if that makes a difference in Apple stores in different states.

Crack (I took a picture of the white screen to get a clearer image of the crack)

Bezel Scuff