For any live event, the most fail-safe option is to have all media stored on your local drive. This can be costly or time-consuming for videos hosted on services like Facebook or YouTube. Certainly, when building, rehearsing and refining your projects, it's easiest to stream directly from those services.
When on-line, MPV provides the cleanest streaming option for YouTube videos. It is the only viable option for Facebook and DailyMotion. When offline, you can still stream from YouTube, but you must first enroll in YouTube premium, download the videos, and stream them with a browser.
On the Stream Tab of the Media screen, you will see this icon. This button allows you to quickly switch all YouTube streams from MPV to Browser and back again.