Thanks for the request, however the “Insert into post” button is not relevant to this field type, as the gallery field is a very custom interface and would not comply with the_editor. Also, what if the user does not have the_editor in their post_type?
As for the set as featured image. I would have thought this would be a link already available for each image in the sidebar information.
Welcome to the Advanced Custom Fields community forum.
Browse through ideas, snippets of code, questions and answers between fellow ACF users