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

On the one hand being tl4 does not mean you are staff. If you are tl4 but have no admin or moderator status, you won’t be able to see, edit or move a topic, which is in the staff category. On the other hand the powers of moderators don’t depend on their tl. See Trust Level Permissions Table (inc Moderator Roles). There is no tl in the moderators column.

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