Yeah, newer model GCN's don't have the digital port. Not really important, since you're not going to use your Wii anyway.
Get the PS2 cables, it will make your DVDs better. Not heaps better, but sharper and better-colored.
You have to buy the Wii component cable separately. I heard it was pretty expensive. Can't remember though. I bought mine for a lot of money, because electronics is very expensive here

. However, due to something about the Wii's graphics, you get a lot of jaggy edges with a component cable in Wii games (not really true for GCN games though). If you can get past that (which you will

), it looks great.