Is it possible to have limited in-app quantity of an iap item? Let's say I have a premium gun which is limited to 100 quantity for the whole game. Is it possible to show the quantity remaining and hide once 100 quantity gets sold? Thanks!

I'm planning to publish a book where the book contains some of the games which are popular. Can I use the app screenshots or app icons available on apple store? What is the license of these images? Are they allowed to be published in a physical book? Are these allowed to be used in a paid web app or website? Thanks!