OK - then I would "reinstall" the default templates running
... and again wait for AD replication. This usually fixes all sorts of weird issues that had happened to the default templates.
(More information here)
As for the MMC test / empty list: You might need to run gpupdate /force at the client (even if the "client" is the CA itself) to download the list of templates to the registry. But I would then only repeat the test after the issue with the OID had been fixed.
Hope this information can help you