I\'m developing android application with Google Services Gradle Plugin(It is needed from Firebase), and the plugin needs google-services.json.
I think the json file
1) Yes, it should - it contains sensitive information like your API key.
2) I don't think so
3) You can use similar aproach as in https://circleci.com/docs/2.0/google-auth/
in your circle.yml decode this variable to google-services.json file in your app directory. In my case I use
echo $GOOGLE_SERVICES | base64 --decode > ~/${HOME}/app/google-services.json