How to increase the width of the article container

That template has a predefined max-width (840px) for the article view area. That's why to make it wider you have to use Custom CSS:

.com-content.view-article #sp-main-body .article-body {
  max-width: 100%; }

Besides, remember to enable that: Template Options > Blog > Details > Full-width Layout: On 

To make a full-width article container.

How to change the Bottom/Footer section?

At the bottom of the template, we used the modules published on positions "bottom1" and "footer1".

Footer1 - with a Copyright note