Please consider that NewsPress is specially designed for Newspaper and Magazines. Users may want to show Advertisements in the Sidebar. So it is not possible to disable the Sidebar from the Options but it can be disabled by some Custom CSS Techniques. You can Remove the Archive WidGet and can show anything like image, text etc. using Text WidGets from Appearance > WidGets
NewsPress Extend has more features to control the Theme Functions. You may feel interest on Reading NewsPress Introduction
