It was available in stores at least for a short while.
Either weren't available, didn't want to do it, or the producers wanted new people. Personally, I like the part 2 designs better.
Not really. The idea that what we think is real isn't is as old as every other idea. There's nothing new under the sun, kid, and there's no such thing as a truly original idea.
-SPOILER-
No and no. The first question has been answered elsewhere. A good explanation of the story background was included in one of the fansub releases. I don't have time to look it up right now, though.
Oh, and that button just below "Enter" on your keyboard is a shift key, and the three to the left of it are for punctuation. Using them will make reading your posts a lot easier and raise my consideration of your intelligence by quite a bit.