Hello
1. You can contact your hosting provider to help you backup data.
also this is some page to show you more information of using childtheme to customize code:
https://codex.wordpress.org/Child_Themes
Tutorial Child Themes – What They Are, How to Use Them, and Why
2. You can hide partner info in Traveler Settings > Partner options > Show email contact info.
3. You can use this css code in Traveler Settings > Styling Options > Custom Css to remove traveler widget:
.demo_changer {display: none; }
Thanks.