If you can convince your stakeholder(s) to forgo a carousel, that is always the best option, as a static hero image is much easier to implement on the front page of a Drupal site and can be just as effective (if not more). If freshness of the front page is a concern, the hero image can always be swapped out manually on a regular basis.
Drupal 8 includes the popular What You See is What You Get (WYSIWYG) editor CKEditor, but out of the box it only provides the 'minimal' configuration, which is missing a lot of the features you may have come to enjoy when implementing CKEditor in Drupal 7 using the CKEditor module and the full version of CKEditor.
Mercury recommends adding an item to a manual feed, for easiest sharing (so that a single piece of content is authoritative and gets updated by the person who knows most about it). However, sometimes you may want to copy an item within Mercury.