Centering items on homepage, full-width issues

I’m having a couple of issues on this homepage and would appreciate any help I can get. Cause I’m stuck.

https://www.wabi.dreamhosters.com/

1. Even though the page template is selected for full width on the backend, the template seems to be leaving a space for a right sidebar in the main content area of the page (the “Non Profit Partners” section below the featured pages). The result is that the centered title in the page content is not centered with the other centered items (like the logo) on the page. How can I make “full width” be truly full width, without the (unused) right sidebar?

2. The screen is overly wide — I get a horizontal scrollbar in my browser when viewing the site in Safari and Chrome — and the green in the body spills over to the right (and climbs up into the header are and down the footer area on the right). I want each section of the site (header, body, footer) to be the same width so the green doesn’t bleed. How would I achieve this?

3. Along these lines, is it possible to make the entire site fixed width (say 1200 pixels) and thus eliminate the menu and other items jumping around when the screen resolution changes?