Database Monitoring from REST API

We have a requirement to monitor database using REST APIs.
Questions:-

  1. create an ID for Rest API monitoring purpose. What access we can give for both Cluster / bucket monitoring which can use REST API?
  2. I did not find all the set of counters we should monitor in any of the documentations which is available online. Can you please provide list of counters to be monitored at both cluster level and bucket level and what threshold we can set in our perl / python script?
  3. What RESTAPI url we can use for cluster monitoring? For example. node is out of sync, need to rebalance, failed over.

For point 3, we have enabled alerting at CB console but seems not enough.

Thanks

Can someone please assist on this?