Repoint does initialize before any content[1] is loaded to the repo. So, you will have to find an alternate approach to add the OOTB group to the custom group. One approach I could think of is to do it via custom code when your code initializes for the first time after AEM restart  [1] https://exper...

From what I can check internally, there are no plans for the near future. You can log a support ticket(provide business impact) for it to be prioritized with the product team.

Can you setup a DEBUG level logger on "com.day.cq.analytics.testandtarget" and try again?Share the logs once done

Change dispatcher.log to TRACE levelTrigger a request and see what is getting logged for that request.Check if the user that is used to start dispatcher has create/edit permissions on the docroot directoryCheck if the docroot directory definition is missing in the dispatcher config.

Undo option is not activated OOTB. Go to [1] and check the details to activate it. Once activated, you can undo any changes. [1] https://experienceleague.adobe.com/docs/experience-manager-65/administering/operations/config-undo.html?lang=en#default-configuration 

Can you try to stop the bundle/service named "com.aem.demo.core.models.HelloWorldModel" and try again? It seems like that service is not correctly instantiated

Yes, you can achieve that by Add the multivalue properties cssProcessor and jsProcessor on the clientlibrary node. See [1] for more details [1] https://experienceleague.adobe.com/docs/experience-manager-65/developing/introduction/clientlibs.html?lang=en#usage 

Setup a DEBUG level logger on the following classes: org.apache.jackrabbit.oak.security.authentication.ldaporg.apache.jackrabbit.oak.spi.security.authentication.external Once done, try to access AEM via LDAP and notice what you get in the logs.

AEM 6.1 has been out of support for a long time. 6.2 and 6.3 have also been out of support. So, I would recommend upgrading as soon as possible. That said, for recovering a username's password, you need to login via admin and go to /useradmin to reset the password

You can find detailed docs related to headless AEM and templates at [1] [1] https://experienceleague.adobe.com/docs/experience-manager-learn/getting-started-with-aem-headless/content-services/chapter-4.html?lang=en#understanding-the-role-of-templates-in-aem-content-services