Thank you both for the information provided. When I originally started this project I had studied the chart linked and decided that the AWS ES instance should meet our needs. I realize the Xpack features aren't supported by AWS ES but it appears to me that AWS ES still supports alerting as described here, plus the alerting UI exists in AWS ES as well. What am I misunderstanding here? Is AWS ES Alerting not analgous to watchers?
For what it's worth I tried my best to pitch the full features ES hosting to my boss but was shot down due to hosting environment concerns. After re-reading the comparison chart now I realize that yalls solution is hosted in AWS as well.
I made have made a grave mistake 
This is why you don't give the new guy with zero elastic experience the task of migrating production clusters 