I am using inline entity forms to allow users to add or reference existing location content to event content from the front end and am very pleased with how this works. I would really like for the buttons to be labeled slightly different here with the labels reading, for example, "Add new location" rather than "Add new node" which is currently a bit confusing for users. Is this possible, even if this was a theme hook that only changed the label in the front end? The solutions for Drupal 7 don't seem to work in 8.
Turns out this is really easy. Under "Manage form display" in your content type, make sure that the widget is set as Inline entity form (simple or complex) and check "Override labels" then define your node type label.