Hey Indi,
1) I'm actually curious to know how long something photoread can stay there before you activate it. It says to let it incubate for 24 hours if possible, but if I wait a week, should I start over again? Alas, I don't know the answer to this question.
2) Playing music *should* be okay, as long as you stay relaxed. I used to play Daft Punk Band, and found out that my *happy* music was way to distracting, since I started dancing in my seat. I switched to classical music (Bach, Al Belini) and have been getting decent results with it. I would avoid it for the photoreading step, but I usually read at Au Bon Pain, so I need something to replace the noise.
3) You can activate those books. It says if possible 24 hours later, at the least 20 minutes, so I'm pretty sure you could activate any of those six books.
Good luck!
-Ramon http://razor.ramon.com