I traced my compilation error to the c2 admob plugin calling our some depreciated api. 
Ashley this is part of the build log error provided by the site build.
BUILD FAILED
Total time: 13.755 secs
Error: /project/gradlew: Command failed with exit code 1 Error output:
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
/project/src/com/cranberrygame/cordova/plugin/ad/admob/AdMobOverlap.java:576: error: AdMobOverlap.MyRewardedVideoListener is not abstract and does not override abstract method onRewardedVideoCompleted() in RewardedVideoAdListener
class MyRewardedVideoListener implements RewardedVideoAdListener {
^
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
1 error
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':compileReleaseJavaWithJavac'.
Compilation failed; see the compiler error output for details.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
at ChildProcess.whenDone (/project/cordova/node_modules/cordova-common/src/superspawn.js:169:23)
at emitTwo (events.js:106:13)
at ChildProcess.emit (events.js:191:7)
at maybeClose (internal/child_process.js:877:16)
at Process.ChildProcess._handle.onexit (internal/child_process.js:226:5)