You might want to handle your PE for a while before you decide on a case. I have mine skinned (decal girl, gelaskin on my EE) but no permanent case. I almost never fold it the way you're talking about. Instead I hold it like a book or put it in a bookstand with both screens facing me. The EE I do use with one screen up and one flat sometimes.
XOskins makes a screen protector which seems strong but is too shiny IMHO. I use it anyway for both screens on my EE. My PE has a cheaper matte screen protector. They give a different sound, or feel, to the screens. So far no problem whatsoever using the Wacom stylus with either screen protector.
You seem like a person who might have a USB keyboard lying around unused. I dug up an old gaming keyboard from our back room and it works just fine.
I
think we have a full version of Docs to Go which
should entitle us to updates, no??