SEP 14.3.x
For Point 1 : It is working as designed. LegacyDomain is used for the legacy SEP clients integration.
For Point 2 : Working as designed.
For Point 1 : It is working as designed. LegacyDomain is obsolete and will be removed in future release.
For Point 2 : A "Domain" filter is planned to be added for System - Server Activity log in future release.