BSD license as opposed to commercial pay-only license key required for building in RoboVM. It's a pretty clear choice for anybody wanting to use this well into the future..
Technically we don't support running the Avian VM on Android, although it should work with minimal porting. However, we support using the VM with any of three class libraries: Android's, OpenJDK's, or Avian's. So, ironically, you can use Android's class library with Avian on every platform you listed except Android :)
If there's interest in porting Avian on Android, we could do it, but since it already has Dalvik/ART, I'm not sure there's much of a point.