Hello,
1) We don’t know what changes did your developer to implement that watermark. If he made changes directly in parent theme files then you lost it because it’s not allowed to change parent theme files if you plan to update the theme. So, contact your developer and clarify the situation with his customization. Ask him if he made changes in the parent theme and if yes then ask him to fix the problem and make changes in the child theme only. We are not responsible for third-party customization.
2)
our site has right click, highlight, copy, save content and image features all disabled, so that no one can take any content from our site, and now none these features are working.
I see that you use a third-party plugin to implement that and don’t see any issues with that. All of the mentioned options are blocked.
Regards