I've never used a screen protector on mine and have never had a problem. Of course, I rarely use the stylus to poke around on the screen.
I've never looked for a replacement stylus because I haven't lost mine yet!
For extra protection when transporting in my backpack, I put the reader in a cheap, padded envelope. works like a charm.
I don't use the giant protective case that comes with it. That thing is just too bulky imo.
Hope you get it soon. I love mine!