The intent is for my actor to react to his video appearing on a close facsimile of the YouTube trending page, and the display itself would be visible as part of the scene while the actor is looking at it. Since getting it on the actual page is out of the question, is there a tool or some other way to fake the content of any such social media sharing site? Diving into the HTML code yielded no results, and the Youtube mockup tool is only for ads, and is very limited.
You can change the source with the developer tools of most web browsers. See this guide: https://skillcrush.com/2015/12/22/how-to-hack-beyonces-twitter-in-under-5-minutes/