A lot unexplained (Pkmn white 2)

I just beat Pokemon White 2 today and I feel like there were so many questions left unanswered! But maybe that's just me thinking about it too much... xD

1. What's wrong with Ghetsis' right arm and eye?
2. How did he find N, Anthea, Concordia and the Shadow Triad.
3. Did he travel to the Sinnoh region?
4. Did Darkrai kill the little ghost girl?
5. What's up with Alder and Ghetsis?
6. What happened to the previous protagonists?

I guess this could be some proof that something is up with Ghetsis' arm/hand. Here is some dialogue.

"...But first, I'll take down this disgusting Trainer with my own hand! This time I WILL succeed! No matter what they try, no one will be able to stop me!"
And here is a picture of his arm/hand from the intro to b/w.
External Image

I have many, many more too!
If anyone could answer any of those, I'd appreciate it!

End