Client's online publication has a lot of contributors with specific guidelines, some contractual.
Posts are not always created or edited by the contributor, so we need a way to populate these guidelines in a sidebar metabox when posts are added or edited so the editor knows what they can and cannot do. These guidelines are specific to the author or contributor selected, not universal.
Something like this: The post is created, author or contributor in dropdown selected, then the post is saved. On next load, a metabox is populated with that author's or contributor's specific guidelines.
Open to a variety of solutions, including: PHP, ACF, Toolset, GenerateWP, Metabox, etc.