No answers, so I had do do more digging.
It turns out one can only have
ONE HDFS (or Hive for that matter) resource based service active at one time, and the value is set in /etc/hadoop/conf/ranger-hdfs-security.xml , key ranger.plugin.hdfs.service.name
Moreover, when set through Ambari, the service name is always <cluster_name>_hadoop (some say it's _hdfs, but I definitely see it as _hadoop in HDP 2.6.3
So, play as much as you want in the Ranger UI, create services, change names, that is just a a fake UI. The real work is done in the /etc/hadoop/conf/ranger-hdfs-security.xml
Thanks guys for making it so straightforward.