Screen the SGP5 is acrylic I think. I put a screen protector on mine first thing. I got a Lexerd protector off Amazon, easy install, has lasted a year and still going strong. Did the same for hubby's player. I recommend the clear over the anti-glare.
The good news is that acrylic may not break as easy as glass and the weight is less. My device has been dropped twice with no injuries, once on thin carpet, once on hardwood.
As for stylus, I think any capacitative stylus should be fine for the player. For Kindle, I think the new Paperwhite has a capacitative screen.
Me, I just use my fingers.