Its cool. I get asked these questions alot :p (And about time. I was barley noticed before this IC day XD)
Pretty much anyone can control NPC characters with a few exceptions, such as Gary Oak which is controlled by yellow or me. Classes pretty much end whenever and go by about one class a day. The classes will tend to last a little while if you let them.
Alot of the classes already started so that may be tough. If all else fails though, your free to go to any of the NPC classes displayed on the first page of the OOC.
That's true. However I did not do the assigning this day. If you wish to be assigned a class, you should ask Megaman765, the other GM, about that. He might still be willing to do that.