While it’s a different Fediverse platform, NeoDB is very, very good, and offers a handful of different apps.

NeoDB can do book reviews and tracking, in addition to TV shows, movies, podcasts, and video games.

There’s none unfortunately. It doesn’t have an API yet. Your best bet is a PWA on iOS.

For Android there’s one in fdroid which is basically a browser that takes care of your login.