We need to include :

• AndroidManifest in push apps only need the DefaultSender instead of the services, receivers, etc (see https://github.com/secondsun/unified-push-helloworld/commit/2a7750ac294db3ae45045a37919c6a8d4d9661ca)
• Documentation on adding google services plugin (see https://github.com/secondsun/unified-push-helloworld/commit/4c18122710754c1516eab2602ec0bb158528d8ae#diff-dc46f9f5dfe204e394fb41395ccd03cfR34 the android/app/build.gradle and android/build.gradle files)
• Documentaiton on how to get google-services.json

I believe this is everything.