EDIT: I should emphasize, I have flavors, for which I don\'t want to use any of these Google services, and attempting to apply the google-services plugin in such a case, wit
I've found interesting workaround. Try the following:
put your google-services.json to any sample app google provides for Firebase integration. Compile it. 
Take a look on path app/build/generated/res/google-services/debug/values/  there should be generated values.xml file with bunch of strings mentioned in errors you described. Copy these strings to value.xml file of your project. That's it.