@brookmatthiesen:
1 & 2) Yes, you are not supposed to edit/add files inside catch-responsive
theme directory. As it will be reverted back to original when you update or upgrade the theme. If you want to change any core functions, then you need to build child theme and edit it in your child theme functions.
Change Featured Slider in Catch Responsive Free theme
— Catch Responsive theme only have option to change that Featured Demo Slider to Featured Slider type”. So, go to “Appearance => Customize => Featured Slider Options” and under “Featured Slider Type”, you need to select “Featured Page Slider”. Then select the pages which you want to show as slider. When you select page, make sure your page have Featured Image.
For more check out theme instructions page at http://catchthemes.com/theme-instructions/catch-responsive/
3) For menu, you can build custom menu from “Appearance => Menus”, and then add in page, post, category, links as per your need. Then you need to assign your custom menu to particular theme location from “Appearance => Menus => Manage Location”. For more check out http://catchthemes.com/blog/videos-blog/video-series-creating-wordpress-custom-menus/
4) You can create submission from using plugin such as Contact Form 7 or JetPack plugin “Contact Form” module.
5) If you upgrade to pro version, then you will have option to add or remove widget in Header Right Sidebar from “Appearance => Widgets”. To know more about pro version, read theme instructions page at http://catchthemes.com/theme-instructions/catch-responsive-pro/
For free, you can add in following css in “Appearance => Customize => Theme Options => Custom CSS Options” box:
#header-right-search.widget_search { display: none; }
6) This option is only there in Pro version.