In JBoss EAP 7.1.0.DR11 Web Management Console in Configuration: Subsystems > Subsystem: EJB 3 > Container configuration screen, the Default security domain field provides suggestions/autocomplete for legacy security domains. With EAP 7.1, Elytron security subsystem will also be provided, so the field should suggest Elytron security domains too.

Another missing thing is support for the application-security-domain mappings (the resource at /subsystem=ejb3/application-security-domain=*) which are used to enable usage of Elytron security domains by applications.