Depending on your seucirty settings, the sudo command will trigger a password inquiry. You do have a strong password on your protected root account, right?
Or is it the default 'raspberry'? I'm personally awful and always forget to change that.
That's awesome that you got the touchscreen working. I have two sitting in a drawer that I've never gotten around to. Are any of the GPIO pins still available to you, or are you planning on using it primarily as a tablet?
Looks that way. Here's the official info in depth.
My SmartiPi kit doesn't use the GPIO header at all, and includes an optional computer cover with full pin access, or can be used without a cover for hats. I am only using two pins for a fan right now.