You are on the right path, but I think there may be something missing in the authorization setup. Personas HTML can indeed be accessed via the HTML GUI (webgui), but if everything is configured correctly, you should have a Personas button in the toolbar when starting the webgui, like this:
Double-check how the related role and corresponding profile is set up in PFCG. If all authorizations are specified for object /PERS/AOBJ then try to see if adding the other two /PERS/* objects with full authorizations would help.