Thank you for your help and suggestions. Turns out the firebase plugin was the culprit. I verified this by uninstalling it and then building my app with success. I resolved this error with the following steps:
- delete /platforms/android folder (take backup first for safety)
- ionic cordova plugin remove cordova-plugin-firebase
- ionic cordova run android (confims that app will build/run but console displays warnings of “missing cordova-plugin-firebase” <= which is expected)
- ionic cordova plugin add cordova-plugin-firebase@2.0.5
- ionic cordova run android
Ultimately it was a matter of updating the firebase plugin.