Hey John!
First of all, thank you for the purchase!
The options you mention are not a part of the theme’s native functionality, but are rather easy to achieve:
1). to have the actual-size background image in the top center position on the page, please download this custom template file, unzip it, and upload via ftp into the theme’s folder (wp-content/themes/Fuji), replacing the existing file.
2). the easiest and most feature-rich plugin that enables setting different backgrounds for each individual page (and even background sliders) is WP Supersized; I highly recommend it and have been using it myself for a long time. Please note that the background created using this plugin will not be positioned as in the first point, i.e. will still stretch the entire screen.
In case this does not fully solve the problem or I can be of any other help, do tell! :)
Sincerely,
Andrew | Satori