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!

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!