The one I have is not compatible with styluses, to my knowledge, I don't mark up my books. As for blue light, I am not sure. I use a standard black and white ereader, with the brightness set to 5%, just enough to be readable in total darkness, thanks to the e-ink screen any light is just a bonus, not a detractor.

I hate reading off of OLED or LCD, VA, etc for any extended period of time, so E-Ink is the way to go for me.