Since the Android TV leanback library is apparently compatible with SDK level 17, which is what the Amazon Fire TV uses, I set the minimum SDK level on my Android TV app and installed it using ADB on my Fire TV. It actually works without any problems. However, it doesn't appear in the apps list in Settings, so I can only launch it through ADB. And when I tried to do a Live App Test in the Amazon Developer console, it won't even install.
Are there some settings or something I can change to make it work correctly? It would be a pity to not be able to use the leanback library since it does actually work, and since Amazon hasn't really provided anything equivalent to it.