Thanks for reaching out. Here's how you can block users on YouTube: https://goo.gl/3uRQAF . Let us know if that helps!
Yes, this will block the contact from seeing or commenting on content you've posted.
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Yes, this will block the contact from seeing or commenting on content you've posted.