If you can, go ahead and cross post in the General Sys Mgt forum where the OMSA guys hang out.
Also, some info at delltechcenter.com/omsa
You might find the support matrix on that site.
For the OME part of the question..
OME will discover a Windows server that has OMSA installed via SNMP or WMI.
OME will discover a Linux server installed via SNMP.
So check the First Time Setup Tutorial in the tutorial section of the OME console. It will go over some of these settings. Also the video and I think whitepapers on delltechcenter.com/ome will list some of the SNMP settings you need. Basically you need to enable SNMP traffic on the Linux server in the snmp.conf. And you need to direct SNMP traps/alerts to the IP address of the OME server.