You probably only need the iPad. The iPad is great for giving you access to most stuff until you get home and can do the more serious work. If you absolutely must do your work away from home, get the Macbook Pro, because iPads are great, but as you mentioned, they don’t have a desktop OS, and that’s a limiting factor.
I am in North America.
I got my preorder from Amazon this week. The error they reported was just the release date being too early on their records.