Zammad - few questions is x,y,z possible

The way the time accounting works for agents is described here:
https://user-docs.zammad.org/en/latest/advanced/time-accounting.html

The configuration is described here:
https://admin-docs.zammad.org/en/latest/manage/time-accounting.html

How the time acccounting behaves entirely depends on your configuration. Technically you can be asked on every ticket update (as long as an article is involved) to add more time to the total time.

Users are always automatically created with a new incoming mail if Zammad doesn’t know the user yet.

The how to add email accounts part is described here:
https://admin-docs.zammad.org/en/latest/channels/email/index.html

Don’t forget to set the outgoing mail address on the related groups.

No. You have to copy paste that yourself.

You can add as many custom objects as you want:
https://admin-docs.zammad.org/en/latest/system/objects.html

However, your use case is fairly specific and most likely at many parts will not work as expected for you.

Technically, yes.

Yes.

Sorry I’m skipping that wall.
You can use reporting with Zammad and Grafana connected to it’s Elasticsearch. That allows you to define much more granular reports. However, you have to figure that out yourself I’m afraid.