Hi Carroll,
Sorry for the delay getting back to you.
Yes, the SRM-MDM Catalog can be very confusing, primarily due to it's reliance on a specific release version of the core MDM system,
On your MDM Catalog server, you will need two SIDs now since it uses the traditional SAP startup framework and you have two instances on the server (one for MDM Catalog and one for the Java stack). However, that should not be an issue. It will just add another entry to the /usr/sap/sapservices file for the new SID. You cannot have the same SID name more than once on a server.
You should be able to use the same version of Java that you use on your SRM server on the MDM server. Also, it's possible to use the SRM Java stack instead of creating a new one on your MDM server. We were originally set up that way but were seeing performance issues on the production SRM server due to Java issues with the catalog.
Make sure you have the correct core MDM version for your SRM-MDM catalog 7.02 installation, including the desktop GUI clients (console, data manager, import manager, etc). There are notes out there (for example, 1083126) that can help mapping the correct SRM-MDM Catalog release version to its correct core MDM release version. If you get these wrong, you will not be able to open or use the repositories in the console.
Hope this helps. Let me know if you need any additional information.
regards,
WL