OPM can only be connected, and send incident information, to one UM 6.1 server. As such, there is no facility to fan-out incident data from OPM to more than one UM 6.1 server.
The connection cannot be tested, outside of an incident being generated and sent to a UM 6.1 server. One can, however, inspect the audit log from the UM 6.1 server to verify if the connection from OPM has been successfully configured. The audit log is available in both the AutoSupport and the Support Bundle.
Running more than one copy of a MEG tool against the same cluster should be avoided due to the load placed on the cluster by the data collection - dual UM instances double the collection load on the cluster ; an OPM instance would add even more and you may run into resource issues on the cluster.