Change 1000+ of WordPress Featured Images in 5 Minutes! › Forums › Questions and Answers › Remove First Image & Delete from Library › Reply To: Remove First Image & Delete from Library
#1 is possible. You can activate the deletion of the first image in the post after it is set as featured image.
#2 is not possible. Since an image has to be in the media library to set it as featured the deletion of it would also result to the removal of the featured image.