According to the build log, you are missing some dependencies.
> Could not resolve all dependencies for configuration ':_armv7DebugCompile'. > Could not find com.google.android.gms:play-services-games:9.0.2.
Check the readme of the plugin you are including to see if it is dependent on other plugins.
Is rare. When I build on a test project only with AdMob plugin built well.
Then when I try to build only with the onesignal plugin also built well.
Then it means that both do not lack any dependence.
The problem is when they are together