Is it possible to make all admin created posts non-editable to all other users?

Did you say that after trying it? I initially moved this topic to an only-admin-editable category on my forum. There are no side effects. There is no such “may” as what you said.

And there are 5 hidden settings related to this topic. rails c to the ruby console environment, then use SiteSetting.tos_topic_id = xxx to set them to whatever topic id you want.

  tos_topic_id:
    default: -1
    hidden: true
  guidelines_topic_id:
    default: -1
    hidden: true
  privacy_topic_id:
    default: -1
    hidden: true
  welcome_topic_id:
    default: -1
    hidden: true
  admin_quick_start_topic_id:
    default: -1
    hidden: true
    client: true

Discourse does has given administrators a lot more rights than other platforms. Please don’t make such comments without trying. I mean, if Discourse were a car manufacturer, you shouldn’t ask it to deliver you Transformers - and all for free.