I don't think that the replication API allows you to modify content (that means: changing the values of properties and/or add/remove nodes) which is then sent only to the publish, but which is not persistet on the authoring instance.

Why do you want to use an existing service-user for code of your own? 

I think that you need to go through an intermediary step of AEM 6.5. That's because with AEM 6.4 some paths in the repository changed (for example /etc/tags moved to /content/cq:tags and some more things), which the migration tools to AEM CS don't handle.  For that reason I would recommend to go thr...

A workflow process step is a piece of code, which runs in the background. For that it is not bound to a HTTP request and also not to a user in the first place. That means that in a process step the concept of a "current user" simply does not exist.

What are you using these deploy scripts for?

Can you please share the ticket ID in private with me?

Yes, maybe I should modify that log message  Thanks for reminding me. It will be fixed in one of the upcoming releases.

That's a nice writeup, thank you! I have debugged a few issues like this already, and it is indeed a common issue, especially if the exception is only happening sporadically. That means that you have a broken version in the dispatcher cache, but when a request bypasses the cache (e.g. by adding a qu...

I have never seen the dispatcher being used as a loadbalancer, and also I am not aware of anyone using it in this role. In 2011 someone in a project of mine tested the dispatcher as loadbalancer and connected it to 6 publish instances. It distributed the requests in a very uneven way (the first publ...

Can't you configure that already on the CI CD pipelines?    "Important metric failure behavior" in https://league.adobe.com/docs/experience-manager-cloud-manager/content/using/pipelines/production-pipelines.html?lang=en#adding-production-pipeline