SOLVED: Customer was using WebLogic 12c which is not supported. Oracle Fusion Middleware 18.104.22.168.0 is certified with WebLogic Server and 10.3.5 and 10.3.6.
Installed and verified WebLogic, created a domain and a test managed server. Everything came up OK including the console. Then wiped the domain and installed WebCenter 11g.
Specified HTTP (not SSL) for all ports. However, I get the JPS-06514 error now when trying to start the admin server. Have followed the online advice, such as deleting cwallet.sso and allowing it to be recreated, chmod 777 cwallet.sso... no change. No more info from setting the debug flag, -Djava.security.debug=jpspolicy.